75 lines
1.5 KiB
C
75 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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int main(int argc, char **argv)
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{
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int p, m, n, a, b, c, count, max = 0, res = 0, tmpa, tmpb, tmpc, i;
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int savedc[1000] = {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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for(p = 12; p <= 1000; p++)
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{
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count = 0;
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a = 0;
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b = 0;
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c = 0;
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for(m = 2; m * m < p; m++)
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{
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for(n = 1; n < m; n++)
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{
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a = m * m - n * n;
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b = 2 * m * n;
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c = m * m + n * n;
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if(a + b + c == p && !savedc[c])
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{
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savedc[c] = 1;
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count++;
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}
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i = 2;
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tmpa = a;
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tmpb = b;
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tmpc = c;
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while(tmpa + tmpb + tmpc < p)
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{
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tmpa = a * i;
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tmpb = b * i;
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tmpc = c * i;
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if(tmpa + tmpb + tmpc == p && !savedc[tmpc])
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{
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savedc[tmpc] = 1;
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count++;
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}
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i++;
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}
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}
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}
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if(count > max)
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{
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max = count;
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res = p;
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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 39\n");
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printf("Answer: %d\n", res);
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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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