forked from github/server
60 lines
1.2 KiB
C
60 lines
1.2 KiB
C
#include <platform.h>
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#include "variant.h"
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#include <assert.h>
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#include <limits.h>
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static int gcd(int a, int b) {
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const int primes[] = { 3, 5, 7, 11, 13, 17, 19, 23, 0 };
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int i = 0, g = 1, p = 2;
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while (p && p <= a && p <= b) {
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if (a % p == 0 && b % p == 0) {
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a /= p;
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b /= p;
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g *= p;
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}
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else {
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p = primes[i++];
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}
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}
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return g;
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}
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static int lcm(int a, int b) {
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int x;
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if (a == b) return a;
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x = (a * b);
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x = (x > 0 ? x : -x) / gcd(a, b);
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return x;
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}
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variant frac_make(int num, int den)
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{
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variant v;
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int g = gcd(num, den);
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num /= g;
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den /= g;
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assert(num >= SHRT_MIN && num <= SHRT_MAX);
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assert(den >= SHRT_MIN && den <= SHRT_MAX);
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v.sa[0] = (short)num;
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v.sa[1] = (short)den;
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return v;
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}
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variant frac_add(variant a, variant b)
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{
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int num, den;
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den = lcm(a.sa[1], b.sa[1]);
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num = a.sa[0] * den / a.sa[1] + b.sa[0] * den / b.sa[1];
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return frac_make(num, den);
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}
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variant frac_mul(variant a, variant b)
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{
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return frac_make(a.sa[0] * b.sa[0], a.sa[1] * b.sa[1]);
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}
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variant frac_div(variant a, variant b)
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{
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return frac_make(a.sa[0] * b.sa[1], a.sa[1] * b.sa[0]);
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}
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