PAT a1107题解

#include <cstdio>#include <algorithm>using namespace std;const int N = 1010;int father[N];int isRoot[N] = {0};int course[N] = {0};int findFather(int x){int a = x;while(x != father[x]){x = father[x];}while(a != father[a]){int z = a;a = father[a];father[z] = x;}return x;} void Union(int a, int b){int faA = findFather(a);int faB = findFather(b);if(faA != faB){father[faA] = faB;} }void init(int n){for(int i = 1; i <= n; i++){father[i] = i;isRoot[i] = false;}}bool cmp(int a, int b){return a > b;}int main(){int n, k, h;scanf("%d", &n);init(n);for(int i = 1; i <= n; i++){scanf("%d:", &k);for(int j = 0; j < k; j++){scanf("%d", &h);if(course[h] == 0){course[h] = i;}Union(i, findFather(course[h]));}}for(int i = 1; i <= n; i++){isRoot[findFather(i)]++;}int ans = 0;for(int i = 1; i <= n; i++){if(isRoot[i] != 0){ans++;}}printf("%d\n", ans);sort(isRoot + 1, isRoot + n + 1, cmp);for(int i = 1; i <= ans; i++){printf("%d", isRoot[i]);if(i < ans) printf(" ");}return 0;}