BZOJ 4668: 冷战

/**************************************************************
    Problem: 4668
    User: BeiYu
    Language: C++
    Result: Accepted
    Time:1256 ms
    Memory:9104 kb
****************************************************************/
 
#include <bits/stdc++.h>
using namespace std;
 
const int N = 5e5+50;
 
int n,lst;
struct UnionTable {
    int f[N],s[N],v[N],d[N];
    void init(int n) {
        for(int i=1;i<=n;i++) f[i]=i,v[i]=0,s[i]=1;
    }
    int find(int x) {
        if(f[x]^x) {
            int fa=find(f[x]);
            d[x]=d[f[x]]+1;
            return fa;
        }else return x;
    }
    void Union(int x,int y,int c) {
        int f1=find(x),f2=find(y);
        if(f1==f2) return;
        if(s[f1]>s[f2]) f[f2]=f1,v[f2]=c,s[f1]+=s[f2];
        else f[f1]=f2,v[f1]=c,s[f2]+=s[f1];
    }
    int Query(int x,int y) {
        int f1=find(x),f2=find(y),r=0;
        if(f1!=f2) return 0;
        for(;x^y;) {
            if(d[x]<d[y]) swap(x,y);
            r=max(r,v[x]),x=f[x];
        }return r;
    }
}un;
 
 
inline int in(int x=0,char ch=getchar()) { while(ch>‘9‘ || ch<‘0‘) ch=getchar();
    while(ch>=‘0‘ && ch<=‘9‘) x=x*10+ch-‘0‘,ch=getchar();return x; }
int main() {
    n=in();
    un.init(n);
    for(int m=in(),c=0;m--;) {
        int opt=in(),u=in()^lst,v=in()^lst;
        if(!opt) un.Union(u,v,++c);
        else printf("%d\n",lst=un.Query(u,v));
    }return 0;
}