CF1726D

随机化冲过去

感谢unrated *2

#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;

struct dsu{
    vi fa,sz;
    dsu(int n){
        fa.resize(n+1),sz.resize(n+1);
        for(int i=0;i<=n;++i)fa[i]=i,sz[i]=1;
    }
    int fnd(int x){
        return fa[x]==x?x:fa[x]=fnd(fa[x]);
    }
    bool merge(int x,int y){
        int oa=fnd(x),ob=fnd(y);
        if(oa!=ob){
            fa[ob]=oa,sz[oa]+=sz[ob];
            return true;
        }
        return false;
    }
};
int tt,n,m,sbctr;

bitset<(int)2e5+9> vis;
vector<pii> v;
bool solve(){
    vis.reset();
    for(int i=0;i<m;++i){
        vis[i]=rand()&1;
    }
    dsu d1(n),d2(n);
    for(int i=0;i<m;++i){
        if(vis[i]){
            if(!d1.merge(v[i].first,v[i].second))
                return true;
        }else{
            if(!d2.merge(v[i].first,v[i].second))
                return true;
        }
    }
    return false;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    srand(time(0));
    cin>>tt;
    f(sb,1,tt){
        vis.reset();
        cin>>n>>m;
        v.resize(m);
        for(int i=1,x,y;i<=m;++i){
            cin>>v[i-1].first>>v[i-1].second;
        }
        while(solve());
        f(i,0,m-1)cout<<vis[i];
        cout<<"\n";
    }
    return 0;
}