80 lines
1.3 KiB
C
80 lines
1.3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <time.h>
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#include "projecteuler.h"
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#define N 10000
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int check_digits(int a, int b);
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int *primes;
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int main(int argc, char **argv)
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{
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int i, j, found = 0;
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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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primes = sieve(N);
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for(i = 1489; i < N && !found; i++)
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{
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if(primes[i])
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{
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for(j = 1; j < 4255; j++)
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{
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if(i + 2 * j < N && primes[i+j] && primes[i+2*j] &&
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check_digits(i, i+j) && check_digits(i, i+2*j))
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{
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found = 1;
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break;
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}
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}
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}
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}
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free(primes);
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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 49\n");
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printf("Answer: %d%d%d\n", i-1, i-1+j, i-1+2*j);
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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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int check_digits(int a, int b)
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{
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int i;
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int digits1[10] = {0}, digits2[10] = {0};
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while(a > 0)
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{
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digits1[a%10]++;
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a /= 10;
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}
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while(b > 0)
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{
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digits2[b%10]++;
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b /= 10;
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}
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for(i = 0; i < 10; i++)
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{
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if(digits1[i] != digits2[i])
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{
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return 0;
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}
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}
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return 1;
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}
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