HDU 3038 How Many Answers Are Wrong 带权并查集

用par[x]表示x的根节点，用ranks[x]表示x到根节点的距离，记得每次都要更新一遍ranks数组（题目中没说有多个输入，结果改了好久才发现加上while后瞬间就ac了。。。）

#include<iostream>
#include<cstdio>
#include<cstring>
#include<ctime>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<set>
#include<bitset>
#include<map>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#define INF 0x3f3f3f3f
#define inf 2*0x3f3f3f3f
#define llinf 1000000000000000000
#define pi acos(-1.0)
#define mod 1000000007
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define lrt rt<<1
#define rrt rt<<1|1
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define per(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define mem(a,b) memset(a,b,sizeof(a))
#define lb(x) (x&-x)
#define gi(x) scanf("%d",&x)
#define gi2(x,y) scanf("%d%d",&x,&y)
#define gll(x) scanf("%lld",&x)
#define gll2(x,y) scanf("%lld%lld",&x,&y)
#define gc(x) scanf("%c",&x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int>P;
/***********************************************/
int n,m,x,y,ss,cnt=0,par[200005],ranks[200005];
int finds(int x)
{
if(par[x]==-1)return x;
int t=finds(par[x]);
ranks[x]+=ranks[par[x]];
return par[x]=t;
}
int main()
{
while(cin>>n>>m)
{
mem(par,-1);mem(ranks,0);cnt=0;
rep(i,0,m)
{
gi2(x,y);gi(ss);x--;
int xx=finds(x),yy=finds(y);
if(xx!=yy)
{
par[yy]=xx;
ranks[yy]=ranks[x]-ranks[y]+ss;
}
else if(ranks[y]-ranks[x]!=ss)cnt++;
}
cout<<cnt<<endl;
}
return 0;
}