//ProjectEuler/Java/Problem11.java //Matthew Ellison // Created: 03-03-19 //Modified: 03-28-19 //What is the greatest product of four adjacent numbers in the same direction (up, down, left, right, or diagonally) in the 20×20 grid? /* 08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00 81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65 52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91 22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80 24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50 32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70 67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21 24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72 21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95 78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92 16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57 86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58 19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40 04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66 88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69 04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36 20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16 20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54 01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48 */ //Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/JavaClasses /* Copyright (C) 2019 Matthew Ellison This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see . */ import mattrixwv.Stopwatch; import mattrixwv.Algorithms; import java.util.ArrayList; public class Problem11{ //This is the grid of numbers that we will be working with private static final Integer[][] grid = {{8, 02, 22, 97, 38, 15, 00, 40, 00, 75, 04, 05, 07, 78, 52, 12, 50, 77, 91, 8}, {49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 04, 56, 62, 00}, {81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 03, 49, 13, 36, 65}, {52, 70, 95, 23, 04, 60, 11, 42, 69, 24, 68, 56, 01, 32, 56, 71, 37, 02, 36, 91}, {22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80}, {24, 47, 32, 60, 99, 03, 45, 02, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50}, {32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70}, {67, 26, 20, 68, 02, 62, 12, 20, 95, 63, 94, 39, 63, 8, 40, 91, 66, 49, 94, 21}, {24, 55, 58, 05, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72}, {21, 36, 23, 9, 75, 00, 76, 44, 20, 45, 35, 14, 00, 61, 33, 97, 34, 31, 33, 95}, {78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 03, 80, 04, 62, 16, 14, 9, 53, 56, 92}, {16, 39, 05, 42, 96, 35, 31, 47, 55, 58, 88, 24, 00, 17, 54, 24, 36, 29, 85, 57}, {86, 56, 00, 48, 35, 71, 89, 07, 05, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58}, {19, 80, 81, 68, 05, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 04, 89, 55, 40}, {04, 52, 8, 83, 97, 35, 99, 16, 07, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66}, {88, 36, 68, 87, 57, 62, 20, 72, 03, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69}, {04, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18, 8, 46, 29, 32, 40, 62, 76, 36}, {20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74, 04, 36, 16}, {20, 73, 35, 29, 78, 31, 90, 01, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 05, 54}, {01, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 01, 89, 19, 67, 48}};; public static void main(String[] argv){ Stopwatch timer = new Stopwatch(); //Allows the program to the timed ArrayList greatestProduct = new ArrayList(); //Holds the largest product we have found so far ArrayList currentProduct = new ArrayList(); //Holds the numbers we are currently working on //Make sure all elements have at least 4 elements for(int cnt = 0;cnt < 4;++cnt){ greatestProduct.add(0); currentProduct.add(0); } //Start the timer timer.start(); //Loop through every row and column for(Integer row = 0;row < 20;++row){ for(Integer col = 0;col < grid[row].length;++col){ //Directional booleans to show whether you can move a certain direction Boolean left = false; Boolean right = false; Boolean down = false; //Check which direction you will be able to move if((col - 3) >= 1){ left = true; } if((col + 3) < grid[row].length){ right = true; } if((row + 3) < 20){ down = true; } //Check the direction you are able to go //Right if(right){ //Fill the product currentProduct.set(0, grid[row][col]); currentProduct.set(1, grid[row][col + 1]); currentProduct.set(2, grid[row][col + 2]); currentProduct.set(3, grid[row][col + 3]); //If the current number's product is greater than the greatest product replace it if(Algorithms.getProd(currentProduct) > Algorithms.getProd(greatestProduct)){ greatestProduct.set(0, currentProduct.get(0)); greatestProduct.set(1, currentProduct.get(1)); greatestProduct.set(2, currentProduct.get(2)); greatestProduct.set(3, currentProduct.get(3)); } } //Down if(down){ //Fill the product currentProduct.set(0, grid[row][col]); currentProduct.set(1, grid[row + 1][col]); currentProduct.set(2, grid[row + 2][col]); currentProduct.set(3, grid[row + 3][col]); //If the current number's product is greater than the greatest product replace it if(Algorithms.getProd(currentProduct) > Algorithms.getProd(greatestProduct)){ greatestProduct.set(0, currentProduct.get(0)); greatestProduct.set(1, currentProduct.get(1)); greatestProduct.set(2, currentProduct.get(2)); greatestProduct.set(3, currentProduct.get(3)); } } //LeftDown if(left && down){ //Fill the product currentProduct.set(0, grid[row][col]); currentProduct.set(1, grid[row + 1][col - 1]); currentProduct.set(2, grid[row + 2][col - 2]); currentProduct.set(3, grid[row + 3][col - 3]); //If the current number's product is greater than the greatest product replace it if(Algorithms.getProd(currentProduct) > Algorithms.getProd(greatestProduct)){ greatestProduct.set(0, currentProduct.get(0)); greatestProduct.set(1, currentProduct.get(1)); greatestProduct.set(2, currentProduct.get(2)); greatestProduct.set(3, currentProduct.get(3)); } } //RightDown if(right && down){ //Fill the product currentProduct.set(0, grid[row][col]); currentProduct.set(1, grid[row + 1][col + 1]); currentProduct.set(2, grid[row + 2][col + 2]); currentProduct.set(3, grid[row + 3][col + 3]); //If the current number's product is greater than the greatest product replace it if(Algorithms.getProd(currentProduct) > Algorithms.getProd(greatestProduct)){ greatestProduct.set(0, currentProduct.get(0)); greatestProduct.set(1, currentProduct.get(1)); greatestProduct.set(2, currentProduct.get(2)); greatestProduct.set(3, currentProduct.get(3)); } } } } //Stop the timer timer.stop(); //Print the resutls System.out.printf("The greatest product of 4 numbers in a line is %d\n", Algorithms.getProd(greatestProduct)); System.out.println("The numbers are " + greatestProduct.toString()); System.out.println("It took " + timer.getStr() + " to run this algorithm"); } } /* Results: The greatest product of 4 numbers in a line is 70600674 The numbers are [89, 94, 97, 87] It took 2.442 milliseconds to run this algorithm */