011.go

/* 
	Project Euler
	Problem 11 - Largest Product in a Grid
	Alex Wormuth (awormuth)
	10/15/217

	Answer submitted: 70600674
*/ 

package main

import (
	"fmt"
)

func main() {
	grid := [][]int{
        { 8, 2, 22, 97, 38, 15, 0, 40, 0, 75, 4, 5, 7, 78, 52, 12, 50, 77, 91, 8, },
        { 49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 4, 56, 62, 0, },
        { 81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 3, 49, 13, 36, 65, },
        { 52, 70, 95, 23, 4, 60, 11, 42, 69, 24, 68, 56, 1, 32, 56, 71, 37, 2, 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, 3, 45, 2, 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, 2, 62, 12, 20, 95, 63, 94, 39, 63, 8, 40, 91, 66, 49, 94, 21, },
        { 24, 55, 58, 5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72, },
        { 21, 36, 23, 9, 75, 0, 76, 44, 20, 45, 35, 14, 0, 61, 33, 97, 34, 31, 33, 95, },
        { 78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 3, 80, 4, 62, 16, 14, 9, 53, 56, 92, },
        { 16, 39, 5, 42, 96, 35, 31, 47, 55, 58, 88, 24, 0, 17, 54, 24, 36, 29, 85, 57, },
        { 86, 56, 0, 48, 35, 71, 89, 7, 5, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58, },
        { 19, 80, 81, 68, 5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 4, 89, 55, 40, },
        { 4, 52, 8, 83, 97, 35, 99, 16, 7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66, },
        { 88, 36, 68, 87, 57, 62, 20, 72, 3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69, },
        { 4, 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, 4, 36, 16, },
        { 20, 73, 35, 29, 78, 31, 90, 1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 5, 54, },
        { 1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48, },
    }

    largestProduct := 0

    for i := 0; i < len(grid); i++ {
        for j := 0; j < len(grid[0]); j++ {
            // Check down
            if i + 3 < len(grid) {
                product := grid[i][j] * grid[i + 1][j] * grid[i + 2][j] * grid[i + 3][j]
                if product > largestProduct {
                    largestProduct = product
                }
            }

            // Check right
            if j + 3 < len(grid[0]) {
                product := grid[i][j] * grid[i][j + 1] * grid[i][j + 2] * grid[i][j + 3]
                if product > largestProduct {
                    largestProduct = product
                }
            }

            // Check diag down right
            if i + 3 < len(grid) && j + 3 < len(grid[0]) {
                product := grid[i][j] * grid[i + 1][j + 1] * grid[i + 2][j + 2] * grid[i + 3][j + 3]
                if product > largestProduct {
                    largestProduct = product
                }
            }

            // Check diag down left
             if i + 3 < len(grid) && j - 3 > 0 {
                product := grid[i][j] * grid[i + 1][j - 1] * grid[i + 2][j - 2] * grid[i + 3][j - 3]
                if product > largestProduct {
                    largestProduct = product
                }
            }
        }
    }

    fmt.Println(largestProduct)
}