在进行并的时候不能瞎jb并，比如（x, y）就必须把x并给y ,即fa[x] = y
1 #include <iostream> 2 #include <string> 3 #include <cstring> 4 #include <algorithm> 5 using namespace std; 6 7 const int maxn = 30000 + 5; 8 int a[maxn]; 9 int fa[maxn]; 10 int Rank[maxn]; 11 int cnt[maxn]; //种类 12 13 int Find(int x){ 14 if (x == fa[x]) 15 return x; 16 int t = Find(fa[x]); 17 cnt[x] += cnt[fa[x]]; 18 return fa[x] = t; 19 } 20 21 void init(){ 22 memset(cnt, 0, sizeof(cnt)); 23 for (int i = 0; i < maxn; i++){ 24 fa[i] = i; 25 Rank[i] = 1; 26 } 27 } 28 29 30 void set_union(int x, int y){ 31 int xx = Find(x); 32 int yy = Find(y); 33 if (xx == yy) 34 return; 35 fa[xx] = yy; 36 cnt[xx] = Rank[yy]; 37 Rank[yy] += Rank[xx]; 38 } 39 40 int main(){ 41 std::ios::sync_with_stdio(false); 42 init(); 43 int t; 44 cin >> t; 45 while (t--){ 46 string s; 47 int x, y; 48 cin >> s; 49 if (s == "M"){ 50 cin >> x >> y; 51 set_union(x, y); 52 } 53 else{ 54 cin >> x; 55 int t = Find(x); 56 cout << cnt[x] << endl; 57 } 58 } 59 //system("pause"); 60 return 0; 61 }