POJ1733

题目链接：https://vjudge.net/problem/POJ-1733

解题思路：并查集+离散化

AC代码：

 #include <iostream>
 #include <cstdio>
 #include <vector>
 #include <algorithm>
 #include <map>
 #include <cstring>
 #include <cmath>
 using namespace std;
 const int maxn=;
 struct query{
     int l,r;
     int oe;
 }q[maxn];
 map<int,int> lists;
 int v[maxn],fa[maxn];
 int finds(int t){
     if(fa[t]==-)
         return t;
     int tmp=finds(fa[t]);
     v[t]^=v[fa[t]];
     return fa[t]=tmp;
 }
 int main(){
 //    freopen("in.txt","r",stdin);
 //    freopen("out.txt","w",stdout);
     int vals[maxn<<];
     char ooe[];
     int ques,len;
     memset(fa,-,sizeof(fa));
     memset(v,,sizeof(v));
     scanf("%d",&len);
     scanf("%d",&ques);
     int j=;
     for(int i=;i<=ques;i++){
         scanf("%d%d%s",&q[i].l,&q[i].r,ooe);
         q[i].l-=;
         if(ooe[]=='e')     q[i].oe=;
         else    q[i].oe=;
         vals[j]=q[i].l;     j++;
         vals[j]=q[i].r;     j++;
     }
     sort(vals+,vals+j);
     int m=unique(vals+,vals+j)-vals-;
     for(int i=;i<=m;i++){
         lists[vals[i]]=i;
     }
     int ending=;
     for(int i=;i<=ques;i++){
         int t1=finds(lists[q[i].l]),t2=finds(lists[q[i].r]);
         int vl=v[lists[q[i].l]],vr=v[lists[q[i].r]];
         if(t1==t2){
             if(vr^vl!=q[i].oe){
                 printf("%d\n",i-);
                 ending=;
                 break;
             }
         }
         else{
             fa[t2]=t1;
             v[t2]=q[i].oe^vl^vr;
         }
     }
     if(!ending) printf("%d\n",ques);
     return ;
 }

额，先这样吧，晚上或者明天再来详谈。