code 1249 B2 并查集

并查集模板题。存一下

问你借书多少天能够循环到开始状态

 

#include <iostream>
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
 
using namespace std;
 
typedef long long ll;
 
int maxn = 100000;
 
 
ll mod = 1000000000 + 7;
 
ll inf = 9223372036854775800L;
 
 
int parent[210000], sum[210000];
 
 
bool cmp(int a, int b) {
    return a < b;
}
 
int find(const int &x) {
    int j, k = x, r = x;
    while (parent[r] != r)r = parent[r];
    //路径压缩
    while (k != r) {
        j = parent[k];
        parent[k] = r;
        k = j;
    }
    return r;
}
 
 
void to_union(int x1, int x2) {
    int p1 = find(x1);
    int p2 = find(x2);
    parent[p2] = p1;
}
 
 
int main() {
    int n, m;
    cin >> n;
    while (n--) {
        cin >> m;
        for (int i = 1; i <= 201000; ++i) {
            parent[i] = i;
        }
        memset(sum, 0, sizeof(sum));
        for (int i = 1; i <= m; ++i) {
            int a;
            cin >> a;
            if (a > i) {
                to_union(i, a);
 
            } else {
                to_union(a, i);
            }
        }
        for (int i = 1; i <= m; ++i) {
            int a = find(i);
            sum[a]++;
        }
 
        for (int i = 1; i <= m; ++i) {
            if (i == m) {
                cout << sum[parent[i]] << endl;
            } else {
                cout << sum[parent[i]] << " ";
            }
        }
 
    }
 
    return 0;
 
}