85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
/* By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from top to bottom is 23.
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*
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* 3
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* 7 4
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* 2 4 6
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* 8 5 9 3
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*
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* That is, 3 + 7 + 4 + 9 = 23.
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* Find the maximum total from top to bottom in triangle.txt (right click and 'Save Link/Target As...'), a 15K text file containing a triangle
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* with one-hundred rows.
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*
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* NOTE: This is a much more difficult version of Problem 18. It is not possible to try every route to solve this problem, as there are 299 altogether!
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* If you could check one trillion (1012) routes every second it would take over twenty billion years to check them all.
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* There is an efficient algorithm to solve it. ;o)*/
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#define _POSIX_C_SOURCE 199309L
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#include "projecteuler.h"
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int main(int argc, char **argv)
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{
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int i, j, max;
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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(100*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 <= 100; 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("triangle.txt", "r")) == NULL)
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{
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fprintf(stderr, "Error while opening file %s\n", "triangle.txt");
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return 1;
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}
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for(i = 1; i <= 100; 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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/* Use the function implemented in projecteuler.c to find the maximum path.*/
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max = find_max_path(triang, 100);
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for(i = 0; i < 100; i++)
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{
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free(triang[i]);
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}
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free(triang);
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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 67\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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