poj 1733 Parity game

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <map>
using namespace std;
const int M = 2e5+7;
int n,q,tot=0;
int f[M],cnt[M],l[M],r[M],op[M],ls[M],num[M];
map<int,int> mp;
void init(int n){//0==even
    for(int i=0;i<=n;i++) f[i]=i,cnt[i]=0;
}
int find(int x){
    if(x==f[x]) return x;
    int tmp=f[x];
    f[x]=find(f[x]);
    cnt[x]^=cnt[tmp];
    return f[x];
}
int main(){
    freopen("1.in","r",stdin);
    freopen("1.out","w",stdout);
    scanf("%d",&n);
    scanf("%d",&q);
    char s[10];
    for(int i=1;i<=q;i++){
        scanf("%d%d%s",&l[i],&r[i],s);l[i]-=1;
        if(s[0]==‘o‘) op[i]=1;
        else op[i]=0;
        ls[++tot]=l[i];ls[++tot]=r[i];
    }
    sort(ls+1,ls+tot+1);
    tot=unique(ls+1,ls+tot+1)-ls-1;
    init(tot);
    for(int i=1;i<=q;i++){
        int posl=lower_bound(ls+1,ls+tot+1,l[i])-ls,posr=lower_bound(ls+1,ls+tot+1,r[i])-ls;
        int fx=find(posl),fy=find(posr);
        if(fx==fy){
            if((cnt[posl]+op[i])%2!=cnt[posr]){
                printf("%d\n",i-1);
                return 0;
            }
        }
        else{
            f[fy]=fx;
            cnt[fy]=(2+cnt[posl]-cnt[posr]+op[i])%2;
        }
    }
    printf("%d\n",q);
    return 0;
}