77 lines
2.1 KiB
C++
77 lines
2.1 KiB
C++
#include <cstdio>
|
|
#include <cstring>
|
|
const int N = 520;
|
|
int a[N + 5], b[N + 5], ta[N + 5], tb[N + 5];
|
|
bool vis[N + 5];
|
|
long long m[N + 5], c[N + 5];
|
|
long long exgcd(long long a, long long b, long long &x, long long &y) {
|
|
if (!b) {
|
|
x = 1;
|
|
y = 0;
|
|
return a;
|
|
}
|
|
long long res = exgcd(b, a % b, y, x);
|
|
y -= a/b*x;
|
|
return res;
|
|
}
|
|
long long mod(long long a, long long b) {
|
|
long long res = a % b;
|
|
if (res < 0) res += b;
|
|
return res;
|
|
}
|
|
void solve(int n) {
|
|
memset(vis, false, sizeof(vis));
|
|
int cnt = 0;
|
|
for (int i = 1; i <= n; ++i)
|
|
if (!vis[i]) {
|
|
int num = 0, t = i;
|
|
while (!vis[t]) {
|
|
vis[t] = true;
|
|
ta[++num] = t;
|
|
tb[num] = b[t];
|
|
t = a[t];
|
|
}
|
|
bool same = false;
|
|
for (int i = 1; i <= num; ++i)
|
|
if (tb[i] == ta[1]) {
|
|
same = true;
|
|
int j = i, k = 1;
|
|
do {
|
|
if (tb[j] != ta[k]) same = false;
|
|
j = j % num + 1;
|
|
k = k % num + 1;
|
|
} while (i != j);
|
|
t = i;
|
|
break;
|
|
}
|
|
if (!same) {
|
|
printf("-1\n");
|
|
return;
|
|
}
|
|
m[++cnt] = num;
|
|
c[cnt] = (num - t + 1) % num;
|
|
}
|
|
n = cnt;
|
|
long long ans = c[1], LCM = m[1];
|
|
for (int i = 2; i <= n; ++i) {
|
|
long long x, y, g = exgcd(LCM, m[i], x, y);
|
|
if ((c[i] - ans) % g) {
|
|
printf("-1\n");
|
|
return;
|
|
}
|
|
ans = mod(ans + LCM*mod((c[i] - ans)/g*x, m[i]/g), LCM/g*m[i]);
|
|
LCM = LCM/g*m[i];
|
|
}
|
|
printf("%I64d\n", ans);
|
|
return;
|
|
}
|
|
int main() {
|
|
int n;
|
|
while (scanf("%d", &n), n) {
|
|
for (int i = 1; i <= n; ++i) scanf("%d", &a[i]);
|
|
for (int i = 1; i <= n; ++i) scanf("%d", &b[i]);
|
|
solve(n);
|
|
}
|
|
return 0;
|
|
}
|