100 lines
2.5 KiB
C
100 lines
2.5 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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*
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* Find the maximum total from top to bottom of the triangle below:
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*
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* 75
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* 95 64
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* 17 47 82
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* 18 35 87 10
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* 20 04 82 47 65
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* 19 01 23 75 03 34
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* 88 02 77 73 07 63 67
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* 99 65 04 28 06 16 70 92
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* 41 41 26 56 83 40 80 70 33
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* 41 48 72 33 47 32 37 16 94 29
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* 53 71 44 65 25 43 91 52 97 51 14
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* 70 11 33 28 77 73 17 78 39 68 17 57
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* 91 71 52 38 17 14 91 43 58 50 27 29 48
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* 63 66 04 68 89 53 67 30 73 16 69 87 40 31
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* 04 62 98 27 23 09 70 98 73 93 38 53 60 04 23
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*
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* NOTE: As there are only 16384 routes, it is possible to solve this problem by trying every route. However, Problem 67, is the same challenge
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* with a triangle containing one-hundred rows; it cannot be solved by brute force, and requires a clever method! ;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(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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/* Use the function implemented in projecteuler.c to find the maximum path.*/
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max = find_max_path(triang, 15);
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for(i = 0; i < 15; 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 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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