ZOJ 1136 Mutiple (同余定理判重)

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
#define sc(x) scanf("%d",&x)
#define pf(x) printf("%d
",x)
#define P printf("
")
#define CL(x,y) memset(x, y, sizeof(x))
#define FOR(i,x,v) for(int i=x; i<=v; i++)
using namespace std;
struct node
{
    int num;
    string str;
};
const int MAX = 5002;
int N, M, arr[10], used[MAX], i, temp;
queue <node> Q;
void BFS();
int main()
{
    int i;
    while(sc(N)!=EOF)
    {
        sc(M);
        FOR(i, 0, M-1)
        sc(arr[i]);
        sort(arr, arr+M);
        CL(used, 0);
        while(!Q.empty ())
            Q.pop ();
        if(N==0) pf(0);
        else
            BFS();
        while(!Q.empty())
            Q.pop ();
//        P;
    }
    return 0;
}
void BFS()
{
    node fir, cur, next;
    fir.num = 0;
    fir.str = "";
    Q.push(fir);
    while(!Q.empty())
    {
        cur = Q.front();
        Q.pop();
//        if(cur.num >= N && cur.num % N == 0)
//        {
//            pf(cur.num);
//            return ;
//        }
        FOR(i, 0, M-1)
        {
            temp = cur.num*10 + arr[i];
            if(!temp) continue;
            if(temp%N==0)
            {
                cout << cur.str << (char)(arr[i]+'0') << endl;
                return ;
            }
            if(!used[temp%N])
            {
                used[temp%N] = 1;
                next.num = temp%N;
                next.str = cur.str + (char)(arr[i]+'0');
                Q.push(next);
            }
        }
    }
    pf(0);
}

虽然错了10次，还是不清楚到底怎么了。。。等几天才懂了那个string 的含义