POJ 1182 食物链（带权并查集）

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//rank[x]==0 表示Father[x]与x同类;//1 表示Father[x]吃x;//2 表示x吃Father[x];#include<stdio.h>#include<string.h>#include<stdlib.h>#include<ctype.h>#include<math.h>#include<stack>#include<queue>#include<map>#include<set>#include<vector>#include<string>#include<iostream>#include<algorithm>#include<utility>#include<iomanip>#include<time.h>typedef long long ll;const double Pi = acos(-1.0);const int N = 1e6+10, M = 1e3+20, mod = 1e9+7, inf = 2e9+10;const double e=2.718281828459 ;const double esp=1e-9;using namespace std;int n,k;int Father[50005];int rank[50005];int Find(int x){    int t;    if(x!=Father[x])    {        t=Father[x];        Father[x]=Find(Father[x]);        rank[x]=(rank[x]+rank[t])%3;    }    return Father[x];}void Union(int x,int y,int d){    int p1=Find(x);    int p2=Find(y);    if(p1!=p2)        Father[p1]=p2;    rank[p1]=(rank[y]-rank[x]+3+d)%3;}int main(){    scanf("%d%d",&n,&k);    for(int i=1; i<=n; i++)    {        Father[i]=i; rank[i]=0;    }    int sum=0;    for(int i=0; i<k; i++)    {        int d,x,y;        scanf("%d%d%d",&d,&x,&y);        if(x>n||y>n||(d==2&&x==y))        {            sum++;            continue;        }        int p1=Find(x);        int p2=Find(y);        if(p1==p2)        {            if((rank[x]-rank[y]+3)%3!=d-1) sum++;        }        else Union(x,y,d-1);    }    printf("%d\n",sum);    return 0;}

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