79 lines
1.5 KiB
C
79 lines
1.5 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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void sum_triangle(int **triang, int n, int i, int j, int sum);
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int max = 0;
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int main(int argc, char **argv)
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{
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int i, j;
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int **triang;
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double elapsed;
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FILE *fp;
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struct timespec start, end;
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clock_gettime(CLOCK_MONOTONIC, &start);
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if((triang = (int **)malloc(15*sizeof(int *))) == NULL)
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{
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fprintf(stderr, "Error while allocating memory\n");
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return 1;
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}
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for(i = 1; i <= 15; i++)
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{
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if((triang[i-1] = (int *)malloc(i*sizeof(int))) == NULL)
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{
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fprintf(stderr, "Error while allocating memory\n");
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return 1;
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}
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}
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if((fp = fopen("triang.txt", "r")) == NULL)
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{
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fprintf(stderr, "Error while opening file %s\n", "triang.txt");
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return 1;
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}
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for(i = 1; i <= 15; i++)
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{
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for(j = 0; j < i; j++)
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{
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fscanf(fp, "%d", &triang[i-1][j]);
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}
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}
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fclose(fp);
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sum_triangle(triang, 15, 0, 0, 0);
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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 18\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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void sum_triangle(int **triang, int n, int i, int j, int sum)
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{
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if(i == n)
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{
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if(sum > max)
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{
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max = sum;
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}
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return;
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}
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sum_triangle(triang, n, i+1, j, sum+triang[i][j]);
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sum_triangle(triang, n, i+1, j+1, sum+triang[i][j]);
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}
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