154 lines
4.7 KiB
C
154 lines
4.7 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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int main(int argc, char **argv)
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{
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int grid[][20] = {{8, 2, 22, 97, 38, 15, 0, 40, 0, 75, 4, 5, 7, 78, 52, 12, 50, 77, 91, 8},
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{49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 4, 56, 62, 0},
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{81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 03, 49, 13, 36, 65},
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{52, 70, 95, 23, 4, 60, 11, 42, 69, 24, 68, 56, 1, 32, 56, 71, 37, 2, 36, 91},
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{22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80},
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{24, 47, 32, 60, 99, 3, 45, 2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50},
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{32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70},
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{67, 26, 20, 68, 2, 62, 12, 20, 95, 63, 94, 39, 63, 8, 40, 91, 66, 49, 94, 21},
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{24, 55, 58, 5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72},
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{21, 36, 23, 9, 75, 0, 76, 44, 20, 45, 35, 14, 0, 61, 33, 97, 34, 31, 33, 95},
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{78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 3, 80, 4, 62, 16, 14, 9, 53, 56, 92},
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{16, 39, 5, 42, 96, 35, 31, 47, 55, 58, 88, 24, 0, 17, 54, 24, 36, 29, 85, 57},
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{86, 56, 0, 48, 35, 71, 89, 7, 5, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58},
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{19, 80, 81, 68, 5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 4, 89, 55, 40},
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{4, 52, 8, 83, 97, 35, 99, 16, 7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66},
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{88, 36, 68, 87, 57, 62, 20, 72, 3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69},
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{4, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18, 8, 46, 29, 32, 40, 62, 76, 36},
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{20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74, 4, 36, 16},
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{20, 73, 35, 29, 78, 31, 90, 1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 5, 54},
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{1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48}};
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int i, j, k, w, max = 0, prod;
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double elapsed;
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struct timespec start, end;
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clock_gettime(CLOCK_MONOTONIC, &start);
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for(i = 0; i < 20; i++)
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{
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for(j = 0; j < 20; j++)
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{
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prod = 1;
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for(k = j; k < j + 4 && k < 20; k++)
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{
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prod *= grid[i][k];
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}
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if(k == j + 4)
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{
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if(prod > max)
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{
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max = prod;
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}
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}
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prod = 1;
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for(k = j; k > j - 4 && k >= 0; k--)
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{
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prod *= grid[i][k];
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}
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if(k == j - 4)
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{
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if(prod > max)
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{
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max = prod;
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}
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}
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prod = 1;
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for(k = i; k < i + 4 && k < 20; k++)
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{
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prod *= grid[k][j];
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}
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if(k == i + 4)
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{
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if(prod > max)
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{
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max = prod;
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}
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}
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prod = 1;
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for(k = i; k > i - 4 && k >= 0; k--)
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{
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prod *= grid[k][j];
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}
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if(k == i - 4)
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{
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if(prod > max)
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{
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max = prod;
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}
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}
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prod = 1;
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for(k = i, w = j; k < i + 4 && w < j + 4 && k < 20 && w < 20; k++, w++)
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{
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prod *= grid[k][w];
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}
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if(k == i + 4 && w == j + 4)
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{
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if(prod > max)
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{
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max = prod;
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}
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}
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prod = 1;
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for(k = i, w = j; k < i + 4 && w > j - 4 && k < 20 && w >= 0; k++, w--)
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{
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prod *= grid[k][w];
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}
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if(k == i + 4 && w == j - 4)
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{
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if(prod > max)
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{
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max = prod;
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}
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}
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prod = 1;
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for(k = i, w = j; k > i - 4 && w < j + 4 && k >= 0 && w < 20; k--, w++)
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{
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prod *= grid[k][w];
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}
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if(k == i - 4 && w == j + 4)
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{
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if(prod > max)
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{
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max = prod;
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}
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}
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prod = 1;
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for(k = i, w = j; k > i - 4 && w > j - 4 && k >= 0 && w >= 0; k--, w--)
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{
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prod *= grid[k][w];
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}
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if(k == i - 4 && w == j - 4)
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{
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if(prod > max)
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{
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max = prod;
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}
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}
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}
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}
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clock_gettime(CLOCK_MONOTONIC, &end);
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elapsed = (end.tv_sec - start.tv_sec) + (double)(end.tv_nsec - start.tv_nsec) / 1000000000;
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printf("Project Euler, Problem 11\n");
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printf("Answer: %d\n", max);
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printf("Elapsed time: %.9lf seconds\n", elapsed);
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return 0;
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}
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