2022_CCPC_华为云计算挑战赛_1006_信道定向

看板子学会的求欧拉回路 :)

#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;

int tt,n,m,tot,hd[(int)2e5+9],deg[(int)2e5+9],mk[(int)4e6+9];
bitset<(int)2e6+9> res;
bitset<(int)2e6+9> vis;
struct edge{
    int to,nxt;
}e[(int)4e6+9];
inline void add(int u,int v){
    e[++tot]={v,hd[u]},hd[u]=tot;
    e[++tot]={u,hd[v]},hd[v]=tot;
}

void dfs(int u){
    for(int &eg=hd[u];eg;){
        if(vis[eg]){eg=e[eg].nxt;continue;}
        vis[eg]=vis[eg^1]=1;
        res[eg>>1]=eg&1;
        dfs(e[eg].to);
    }
}

int main()
{
    int size(512<<20);  // 512M
    __asm__ ( "movq %0, %%rsp\n"::"r"((char*)malloc(size)+size));
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>tt;
    f(sb,1,tt){
        tot=1;
        vis.reset(),res.reset();
        cin>>n>>m;
        for(int i=1;i<=n+1;++i)hd[i]=deg[i]=0;
        for(int i=1,x,y;i<=m;++i){
            cin>>x>>y;
            deg[x]+=1,deg[y]+=1;
            add(x,y);
        }
        for(int i=1;i<=n;++i)if(deg[i]&1)add(i,n+1);
        for(int i=1;i<=n;++i)dfs(i);
        for(int i=1;i<=m;++i)cout<<res[i];
        cout<<"\n";
    }
    exit(0);
}