Project Euler – Problem # 11 – Solved with Go

What is the greatest product of four adjacent numbers on the same straight line in the 20 by 20 grid?

In the 2020 grid below, four numbers along a diagonal line have been marked in red.

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

The product of these numbers is 26 * 63 * 78 * 14 = 1788696.

What is the greatest product of four adjacent numbers in any direction (up, down, left, right, or diagonally) in the 20×20 grid?

One Possible Solution: Go

package main

import "fmt"

func main() {

	Grid := [20][20]int{
		{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},
	}

	Product := 0
	largest := 0

	// Check horizontally
	for i := 0; i < 20; i++ {
		for j := 0; j < 17; j++ {
			Product = Grid[i][j] * Grid[i][j+1] * Grid[i][j+2] * Grid[i][j+3]
			if Product > largest {
				largest = Product
			}
		}
	}

	// Check vertically
	for i := 0; i < 17; i++ {
		for j := 0; j < 20; j++ {
			Product = Grid[i][j] * Grid[i+1][j] * Grid[i+2][j] * Grid[i+3][j]
			if Product > largest {
				largest = Product
			}
		}
	}

	// Check diagonally right
	for i := 0; i < 17; i++ {
		for j := 0; j < 17; j++ {
			Product = Grid[i][j] * Grid[i+1][j+1] * Grid[i+2][j+2] * Grid[i+3][j+3]
			if Product > largest {
				largest = Product
			}
		}
	}

	// Check diagonally left
	for i := 0; i < 17; i++ {
		for j := 3; j < 20; j++ {
			Product = Grid[i][j] * Grid[i+1][j-1] * Grid[i+2][j-2] * Grid[i+3][j-3]
			if Product > largest {
				largest = Product
			}
		}
	}

	fmt.Println(largest)
}
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Project Euler – Problem # 11 – Solved with Java

What is the greatest product of four adjacent numbers on the same straight line in the 20 by 20 grid?

In the 2020 grid below, four numbers along a diagonal line have been marked in red.

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

The product of these numbers is 26 * 63 * 78 * 14 = 1788696.

What is the greatest product of four adjacent numbers in any direction (up, down, left, right, or diagonally) in the 20×20 grid?

One Possible Solution: Java

Project Euler – Problem # 11 – Solved with Python

Problem 11 solved with help from: Help with creating a list of lists

Problem:

What is the greatest product of four numbers on the same straight line in the 20 by 20 grid?

20 x 20 (20×20.txt) file in the same directory as problem_11.py

f = open('20x20.txt', 'rU')
x = []
max_prod = 0

for m in xrange(20):                # Create a list of lists with x
    x.append([])
    for n in xrange(20):
        x[m].append(int(f.read(3)))
                          
f.close()

        # Check horizontally for max_prod...
        
for i in range(len(x)):                 
    for j in range(len(x[i])-3):       
        horiz = (x[i][j])*(x[i][j+1])*(x[i][j+2])*(x[i][j+3])
        if horiz > max_prod:
            max_prod = horiz

        # Check vertically for max_prod...
    
for i in range(len(x[i])-3):        
    for j in range(len(x)):
        vert = (x[i][j])*(x[i+1][j])*(x[i+2][j])*(x[i+3][j])
        if vert > max_prod:
            max_prod = vert

        # Check diagonally right for max_prod...
       
for i in range(len(x[i])-3):        
    for j in range(len(x[i])-3):
        diag_right = (x[i][j])*(x[i+1][j+1])*(x[i+2][j+2])*(x[i+3][j+3])
        if diag_right > max_prod:
            max_prod = diag_right

        # Check diagonally left for max_prod...
            
for i in range(3,len(x)):           
    for j in range(len(x[i])-3):
        diag_left = (x[i][j])*(x[i-1][j+1])*(x[i-2][j+2])*(x[i-3][j+3])
        if diag_left > max_prod:
            max_prod = diag_left

print "Max product = %s" % max_prod

Project Euler