Problem
In the 20X20 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 X 63 X 78 X 14 = 1788696.
What is the greatest product of four adjacent numbers in the same direction (up, down, left, right, or diagonally) in the 20X20 grid?
Sol. 1
#include <stdio.h>
using namespace std;
int main()
{
int arr[30][30];
long long maxx=0;
for (int i = 1; i <= 20; i++)
{
for (int j = 1; j <= 20; j++)
{
scanf("%d", &arr[i][j]);
}
}
for (int i = 1; i <= 20; i++)
{
for (int j = 1; j <= 17; j++)
{
long long v = 1;
for (int k = j; k <= j + 3; k++)
v *= arr[i][k];
if (maxx < v)
maxx = v;
}
}
for (int i = 1; i <= 17; i++)
{
for (int j = 1; j <= 20; j++)
{
long long v = 1;
for(int k=i; k<=i+3; k++)
v *= arr[k][j];
if (maxx < v)
maxx = v;
}
}
for (int i = 1; i <= 17; i++)
{
for (int j = 1; j <= 17; j++)
{
long long v = 1;
for (int k = 0; k < 4; k++)
v *= arr[i + k][j + k];
if (maxx < v)
maxx = v;
}
}
for (int i = 1; i <= 17; i++)
{
for (int j = 4; j <= 20; j++)
{
long long v = 1;
for (int k = 0; k < 4; k++)
v *= arr[i + k][j - k];
if (maxx < v)
maxx = v;
}
}
printf("%d\n", maxx);
}