HDU5348——DFS——MZL's endless loop

/************************************************
Author        :powatr
Created Time  :2015-8-6 19:51:08
File Name     :b.cpp
************************************************/

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
#pragma comment (linker, "/STACK:102400000,102400000");
using namespace std;
#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef long long ll;
const int MAX = 1e5 + 10;
const int MAXN = 7e5 + 10;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;

int head[MAX];
int du[2][MAX];
int sum[MAX];
int vis[MAXN], ans[MAXN];
int n, m, E, u, v;
struct edge{
    int u, v;
    int next;
}a[MAXN];

void inti()
{
    E = 0;
    memset(head, -1, sizeof(head));
    memset(vis, 0, sizeof(vis));
    memset(sum , 0, sizeof(sum));
    memset(du, 0, sizeof(du));
    memset(ans, 0, sizeof(ans));
}

void add(int u, int v)
{
    a[E].u = u;
    a[E].v = v;
    a[E].next = head[u];
    head[u] = E++;
}

void dfs(int u, int y)
{
    for(int i = head[u]; ~i; i = a[i].next){
        if(vis[i]) {
            head[u] = a[i].next;
            //访问过就删去
            continue;
        }
        int v = a[i].v;
        if(v!=u && du[y][v] < du[y^1][v]) continue;
        vis[i] = vis[i^1] = 1;
        if(i%2) ans[i/2] =  y^1;//表示从u到v
        else ans[i/2] = y;
        du[y][u]++;
        du[y^1][v]++;
        head[u] = a[i].next;
        dfs(v,y);
        return;
    }
}

int main()
{
    int T;
    scanf("%d", &T);
    while(T--){
        scanf("%d%d", &n, &m);
        inti();
        for(int i = 1 ; i <= m; i++){
            scanf("%d%d", &u, &v);
            add(u, v);
            add(v, u);
            sum[v]++;
            sum[u]++;
        }
        for(int i = 1; i <= n; i++){
            while(du[0][i] + du[1][i] < sum[i]){
                if(du[0][i] <= du[1][i]) dfs(i, 0);
                else dfs(i, 1);
            }
        }
        for(int i = 0 ; i < m; i++)
            printf("%d\n", ans[i]);
    }
    return 0;
}