26 lines
474 B
C++
26 lines
474 B
C++
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#include <bits/stdc++.h>
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using namespace std;
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typedef long long LL;
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// P1082 [NOIP2012 提高组] 同余方程
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//扩展欧几里得
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LL exgcd(LL a, LL b, LL &x, LL &y) {
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if (!b) {
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x = 1, y = 0;
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return a;
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}
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LL d = exgcd(b, a % b, y, x);
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y -= a / b * x;
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return d;
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}
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int main() {
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LL a, b;
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scanf("%lld %lld", &a, &b);
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LL x, y;
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exgcd(a, b, x, y);
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printf("%d\n", (x % b + b) % b);
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return 0;
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}
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