mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
77 lines
2.1 KiB
C++
77 lines
2.1 KiB
C++
#include <cstdio>
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#include <cstring>
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const int N = 520;
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int a[N + 5], b[N + 5], ta[N + 5], tb[N + 5];
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bool vis[N + 5];
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long long m[N + 5], c[N + 5];
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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;
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y = 0;
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return a;
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}
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long long res = exgcd(b, a % b, y, x);
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y -= a/b*x;
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return res;
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}
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long long mod(long long a, long long b) {
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long long res = a % b;
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if (res < 0) res += b;
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return res;
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}
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void solve(int n) {
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memset(vis, false, sizeof(vis));
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int cnt = 0;
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for (int i = 1; i <= n; ++i)
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if (!vis[i]) {
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int num = 0, t = i;
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while (!vis[t]) {
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vis[t] = true;
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ta[++num] = t;
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tb[num] = b[t];
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t = a[t];
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}
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bool same = false;
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for (int i = 1; i <= num; ++i)
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if (tb[i] == ta[1]) {
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same = true;
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int j = i, k = 1;
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do {
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if (tb[j] != ta[k]) same = false;
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j = j % num + 1;
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k = k % num + 1;
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} while (i != j);
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t = i;
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break;
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}
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if (!same) {
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printf("-1\n");
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return;
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}
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m[++cnt] = num;
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c[cnt] = (num - t + 1) % num;
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}
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n = cnt;
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long long ans = c[1], LCM = m[1];
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for (int i = 2; i <= n; ++i) {
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long long x, y, g = exgcd(LCM, m[i], x, y);
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if ((c[i] - ans) % g) {
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printf("-1\n");
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return;
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}
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ans = mod(ans + LCM*mod((c[i] - ans)/g*x, m[i]/g), LCM/g*m[i]);
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LCM = LCM/g*m[i];
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}
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printf("%I64d\n", ans);
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return;
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}
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int main() {
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int n;
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while (scanf("%d", &n), n) {
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for (int i = 1; i <= n; ++i) scanf("%d", &a[i]);
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for (int i = 1; i <= n; ++i) scanf("%d", &b[i]);
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solve(n);
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}
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return 0;
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}
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