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53 lines
840 B
C++
53 lines
840 B
C++
#include <iostream>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 1e5 + 5;
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int n;
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long long a[N], b[N];
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long long exgcd(long long a, long long b, long long &x, long long &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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long long g = exgcd(b, a % b, y, x);
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y -= a / b * x;
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return g;
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}
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long long CRT() {
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long long mod = 1, ans = 0;
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for (int i = 1; i <= n; i++) {
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mod *= a[i];
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}
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for (int i = 1; i <= n; i++) {
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long long m = mod / a[i], x, y;
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exgcd(m, a[i], x, y);
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ans = (ans + b[i] * m * x % mod) % mod;
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}
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return (ans % mod + mod) % mod;
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}
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int main() {
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std::ios::sync_with_stdio(false);
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cin >> n;
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for (int i = 1; i <= n; i++) {
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cin >> a[i] >> b[i];
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}
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cout << CRT() << endl;
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return 0;
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}
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