2012-2013 ACM-ICPC, Asia Tokyo Regional Contest F.Never Wait for Weights(带权并查集模板)

题目大意：

存在着n个物品，然后有m次操作

！  x y l

表示y比x重l

？ x y

表示询问y比x重多少

解题思路：

这是一道带权并查集的问题，之前没有触及到，所以这次遇到就补充一下

#include<iostream>  #include<cstdio>#include<stdio.h>#include<cstring>#include<cstdio>#include<climits>   #include<cmath> #include<vector>  #include <bitset>  #include<algorithm>    #include <queue>  #include<map> #define inf 9999999;using namespace std;typedef long long LL;int n,T;int fa[100005],rank[100005];int getf(int x){if(x==fa[x])return x;int k=getf(fa[x]);rank[x]+=rank[fa[x]];return fa[x]=k;}void init(){for(int i=1;i<=n;i++){fa[i]=i;rank[i]=0;}}int main(){char s;int t1,t2;int x,y,l,i;for(;;){scanf("%d%d",&n,&T);init();if(n==0&&T==0)break;while(T--){scanf("%s",&s);//cin>>s;if(s=='!'){scanf("%d%d%d",&x,&y,&l);t1=getf(x);t2=getf(y);if(t1!=t2){fa[t2]=t1;rank[t2]=rank[x]+l-rank[y];}}else{scanf("%d%d",&x,&y);t1=getf(x);t2=getf(y);if(t1!=t2)printf("UNKNOWN\n");elseprintf("%d\n",rank[y]-rank[x]);//cout<<rank[y]-rank[x]<<endl;;}}}}