MT3056 交换序列

思路：

与题目 MT3055 交换排列 类似

代码： 

#include <bits/stdc++.h>
using namespace std;
const int N = 1e4 + 10;
int n, fa[N], b[N], d[N];
void init(int n)
{
    for (int i = 1; i <= n; i++)
        fa[i] = i;
}
int find(int x)
{
    return x == fa[x] ? x : (fa[x] = find(fa[x]));
}
void merge(int i, int j)
{
    int x = find(i), y = find(j);
    if (x != y)
        fa[x] = y;
}
int main()
{

    cin >> n;
    init(n);
    for (int i = 1; i <= n; i++)
    {
        cin >> b[i];
    }
    for (int i = 1; i <= n; i++)
    {
        cin >> d[i];
    }
    for (int i = 1; i <= n; i++)
    {
        if (i - d[i] >= 1)
            merge(i, i - d[i]);
        if (i + d[i] <= n)
            merge(i, i + d[i]);
    }
    for (int i = 1; i <= n; i++)
    {
        if (find(i) != find(b[i]))
        {
            cout << -1;
            return 0;
        }
    }
    cout << 1;

    return 0;
}