51 lines
930 B
C
51 lines
930 B
C
#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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/* should be 64-bit integers if going over 1 billion */
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typedef unsigned long xint;
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#define FMT "%lu"
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xint total, prim, max_peri;
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void new_tri(xint in[])
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{
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int i;
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xint t[3], p;
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xint x = in[0], y = in[1], z = in[2];
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recur: p = x + y + z;
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if (p > max_peri) return;
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prim ++;
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total += max_peri / p;
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t[0] = x - 2 * y + 2 * z;
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t[1] = 2 * x - y + 2 * z;
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t[2] = t[1] - y + z;
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new_tri(t);
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t[0] += 4 * y;
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t[1] += 2 * y;
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t[2] += 4 * y;
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new_tri(t);
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z = t[2] - 4 * x;
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y = t[1] - 4 * x;
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x = t[0] - 2 * x;
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goto recur;
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}
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int main()
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{
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xint seed[3] = {3, 4, 5};
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for (max_peri = 10; max_peri <= 100000000; max_peri *= 10) {
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total = prim = 0;
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new_tri(seed);
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printf( "Up to "FMT": "FMT" triples, "FMT" primitives.\n",
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max_peri, total, prim);
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}
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return 0;
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}
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