38 lines
783 B
C++
38 lines
783 B
C++
// https://vjudge.csgrandeur.cn/problem/HDU-1576
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#include <bits/stdc++.h>
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typedef long long LL;
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/*
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测试用例
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2
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1000 53
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87 123456789
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答案
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7922
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6060
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*/
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using namespace std;
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const int MOD = 9973;
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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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int t;
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cin >> t;
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while (t--) {
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LL x, y;
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LL a, b;
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cin >> a >> b;
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exgcd(b, MOD, x, y);
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x = (x % MOD + MOD) % MOD; //对比使用费马小定理，这里对于扩展欧几里得算出的逆元，还需要进一步模一下 MOD才行，否则可能是负的
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cout << (x * a) % MOD << endl;
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}
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return 0;
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} |