HDU 2473 Junk-Mail Filter 删点并查集

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删点并查集，就是用一个新的点标代替之前的点标即可。。 y一下就可以了

#include <cstdio>#include <iostream>#include <algorithm>#include <string.h>#include <vector>#include <map>#include <queue>#include <math.h>#include <string>#include <set>using namespace std;#define mod 1000000007#define ll int#define N 100101ll r[1100010], f[1100010], a[N], top;ll n, m;ll find(ll x){return x==f[x]?x:f[x] = find(f[x]);}void Union(ll x, ll y){    ll fx = find(x), fy = find(y);    if(fx==fy)  return;    if(r[fx]>r[fy])  swap(fx,fy);    f[fx] = fy;    r[fy] += r[fx];}void Del(ll x){find(a[x]);a[x] = top;r[top] = 1;f[top] = top;top++;}void init(){    for(ll i = 0; i < n; i++)        f[i] = a[i] = i, r[i] = 1;top = n;}set<int>s;int main(){int i, j, u, v, Cas = 1;while(scanf("%d %d",&n,&m), n+m){init();while(m--){char c[10]; scanf("%s %d",c,&u);if(c[0]=='M'){scanf("%d",&v);Union(a[u], a[v]);}else Del(u);}s.clear();for(i = 0; i < n; i++) for(i = 0; i < n; i++)s.insert(find(a[i]));printf("Case #%d: %d\n", Cas++, s.size());}return 0;}

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