{"id":132,"date":"2014-04-24T15:43:37","date_gmt":"2014-04-24T22:43:37","guid":{"rendered":"http:\/\/willclausen.com\/?p=132"},"modified":"2014-04-24T15:45:01","modified_gmt":"2014-04-24T22:45:01","slug":"project-euler-problem-11","status":"publish","type":"post","link":"https:\/\/willclausen.com\/?p=132","title":{"rendered":"Project Euler Problem 11"},"content":{"rendered":"

The problem:<\/p>\n

Find the largest product of 4 adjacent numbers in a 20×20 grid. Numbers can be adjacent in any direction, vertical, horizontal, diagonal.<\/p>\n

http:\/\/projecteuler.net\/problem=11<\/p>\n

My solution (in java):<\/p>\n

\r\n\r\n\/\/ Author: Will Clausen\r\n\/\/\r\n\/\/ Date: Jan. 16, 2013\r\n\/\/\r\n\/\/ This program will solve Problem 11 from Project Euler.\r\n\r\nimport java.util.Scanner;\r\n\r\npublic class Problem11 {\r\n\u00a0\u00a0 \u00a0\/\/ Grid to store all the numbers\r\n\u00a0\u00a0 \u00a0int[][] grid;\r\n\u00a0\u00a0 \u00a0\/\/ The number of adjacent numbers to use when looking for the maximum\r\n\u00a0\u00a0 \u00a0int numAdjacent;\r\n\u00a0\u00a0 \u00a0\/\/ Grid dimensions\r\n\u00a0\u00a0 \u00a0int gridWidth;\r\n\u00a0\u00a0 \u00a0int gridHeight;\r\n\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\/\/ To make my solution a little more general, I allow for the specification\r\n\u00a0\u00a0 \u00a0\/\/ of the size of the grid and the number of adjacent entries in the matrix\r\n\u00a0\u00a0 \u00a0\/\/ to consider.\r\n\u00a0\u00a0 \u00a0Problem11(String input, int gw, int gh, int limit)\r\n\u00a0\u00a0 \u00a0{\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Assign variables according to proper input.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0numAdjacent = limit;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0gridWidth = gw;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0gridHeight = gh;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Create scanner for reading from the input string.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0Scanner scanner = new Scanner(input);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0Scanner line;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0grid = new int[gridHeight][gridWidth];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Variables for indexing into the grid when inserting numbers\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int widthIndex = 0;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int heightIndex = 0;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ While there are still things to read from the input.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0while (scanner.hasNextLine()) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Get the next line of numbers for the grid\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0line = new Scanner(scanner.nextLine());\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Take the numbers out of the line and put them in the grid.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0while (line.hasNextInt()) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int nextNum = line.nextInt();\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0grid[heightIndex][widthIndex] = nextNum;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Update the indexing accordingly\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0widthIndex++;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Update indexing accordingly\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0widthIndex = 0;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0heightIndex++;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0line.close();\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Remember to close the scanner.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0scanner.close();\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Method to ensure everything was inputted properly.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printGrid();\r\n\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\/\/ Method to actually solve problem 11.\r\n\u00a0\u00a0 \u00a0public int solve()\r\n\u00a0\u00a0 \u00a0{\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Start with an initial maximum, will be changed during execution.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int maxProd = 1;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Initialize the next product to be checked to the mulitplicative identity.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int nextProd = 1;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ Arrays to keep track of the most recent numbers seen.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int[] horiz = new int[numAdjacent];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int[] vert = new int[numAdjacent];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int[] diag = new int[numAdjacent];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int[] diag2 = new int[numAdjacent];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int[] max = new int[numAdjacent];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ To simplify things, loop through the array in different directions\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ using multiple loops. It adds computation time, but it makes much\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ more sense conceptually.\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ get maximum horizontal product\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int i = 0; i < gridHeight; i++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int j = 0; j <= (gridWidth - numAdjacent); j++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int k = j; k < (numAdjacent + j); k++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0horiz[k % numAdjacent] = grid[i][k];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0nextProd = calcProd(horiz);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0if (nextProd > maxProd) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0maxProd = nextProd;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.println("New max product is: " + maxProd);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("The array is: ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(horiz);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0max = horiz;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(max);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("The final horizontal array is: ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(horiz);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ get the maximum vertical product\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int i = 0; i < gridWidth; i++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int j = 0; j <= (gridHeight - numAdjacent); j++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int k = j; k < (numAdjacent + j); k++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0vert[k % numAdjacent] = grid[k][i];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0nextProd = calcProd(vert);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0if (nextProd > maxProd) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0maxProd = nextProd;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.println("New max product is: " + maxProd);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("The array is: ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(vert);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0max = vert;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(max);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("The final vertical array is: ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(vert);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ get the maximum diagonal product (down and to the right)\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int i = 0; i <= (gridWidth - numAdjacent); i++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int j = 0; j <= (gridHeight - numAdjacent); j++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int k = 0; k < (numAdjacent); k++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0diag[k] = grid[i + k][j + k];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0nextProd = calcProd(diag);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0if (nextProd > maxProd) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0maxProd = nextProd;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.println("New max product is: " + maxProd);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("The array is: ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(diag);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0max = diag;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(max);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("The final diagonal array is: ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(diag);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\/\/ get the maximum diagonal product (up to the right)\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int i = numAdjacent-1; i < gridHeight; i++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int j = 0; j <= (gridWidth - numAdjacent); j++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int k = 0; k < numAdjacent; k++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0diag2[k] = grid[i - k][j + k];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0nextProd = calcProd(diag2);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0if (nextProd > maxProd) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0maxProd = nextProd;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.println("New max product is: " + maxProd);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("The array is: ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(diag2);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0max = diag2;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(max);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int finalProd = calcProd(max);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.println("The product of the final array is: " + finalProd);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0printArray(max);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0return maxProd;\r\n\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\/\/ Helper method for calculating the product of numbers in an array.\r\n\u00a0\u00a0 \u00a0public int calcProd(int[] nums)\r\n\u00a0\u00a0 \u00a0{\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int prod = 1;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int i = 0; i < nums.length; i++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0if (nums[i] == 0) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0return 0;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0} else {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0prod *= nums[i];\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0return prod;\r\n\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\/\/ Helper method for printing the contents of an array of numbers in a nice way.\r\n\u00a0\u00a0 \u00a0public static void printArray(int[] numArray)\r\n\u00a0\u00a0 \u00a0{\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("[");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int i = 0; i < numArray.length; i++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print(numArray[i] + ", ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.println("]");\r\n\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\/\/ Helper method for printing a gird of numbers in a nice way.\r\n\u00a0\u00a0 \u00a0public void printGrid()\r\n\u00a0\u00a0 \u00a0{\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for (int i = 0; i < gridHeight; i++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print("[");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0for(int j = 0; j < gridWidth; j++) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.print(grid[i][j] + ", ");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.println("]");\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0}\r\n\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0 \u00a0\/**\r\n\u00a0\u00a0 \u00a0 * @param args\r\n\u00a0\u00a0 \u00a0 *\/\r\n\u00a0\u00a0 \u00a0public static void main(String[] args) {\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0Problem11 prob11 = new Problem11("08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54 \\n" + \r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0"01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48", 20, 20, 4);\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0int solution = prob11.solve();\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0System.out.println("The solution is: " + solution);\r\n\u00a0\u00a0 \u00a0}\r\n\r\n}\r\n\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
The problem: Find the largest product of 4 adjacent numbers in a 20×20 grid. Numbers can be adjacent in any direction, vertical, horizontal, diagonal. http:\/\/projecteuler.net\/problem=11 My solution (in java): \/\/ Author: Will Clausen \/\/ \/\/ Date: Jan. 16, 2013 \/\/ \/\/ This program will solve Problem 11 from Project Euler. import java.util.Scanner; public class Problem11 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[35,34,36,42],"class_list":["post-132","post","type-post","status-publish","format-standard","hentry","category-project-euler","tag-grid","tag-problem-11","tag-product","tag-project-euler"],"_links":{"self":[{"href":"https:\/\/willclausen.com\/index.php?rest_route=\/wp\/v2\/posts\/132","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/willclausen.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/willclausen.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/willclausen.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/willclausen.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=132"}],"version-history":[{"count":2,"href":"https:\/\/willclausen.com\/index.php?rest_route=\/wp\/v2\/posts\/132\/revisions"}],"predecessor-version":[{"id":134,"href":"https:\/\/willclausen.com\/index.php?rest_route=\/wp\/v2\/posts\/132\/revisions\/134"}],"wp:attachment":[{"href":"https:\/\/willclausen.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=132"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/willclausen.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=132"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/willclausen.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=132"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}