hdu 4474 bfs

和上一题大同小异，经过思考，visit数组可以省去第一维。

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

const int N = 10007;
const int M = 10;
int n, m, head, tail;
bool visit[N];
bool digit[M];

struct Node
{
    int d, r, pre;
    Node(){}
    Node( int _d, int _r, int _pre )
    {
        d = _d, r = _r, pre = _pre;
    }
} q[N];

void dfs( int x )
{
    if ( x == -1 ) return ;
    dfs( q[x].pre );
    printf("%d", q[x].d);
}

void bfs()
{
    memset( visit, 0, sizeof(visit) );
    head = tail = 0;
    for ( int i = 1; i < M; i++ )
    {
        if ( !digit[i] && !visit[i % n] )
        {
            q[tail++] = Node( i, i % n, -1 );
            visit[i % n] = 1;
        }
    }
    while ( head < tail )
    {
        if ( q[head].r == 0 )
        {
            dfs(head);
            putchar('
');
            return ;
        }
        for ( int k = 0; k < M; k++ )
        {
            if ( digit[k] ) continue;
            int rr = ( q[head].r * 10 + k ) % n;
            if ( !visit[rr] )
            {
                q[tail++] = Node( k, rr, head );
                visit[rr] = 1;
            }
        }
        head++;
    }
    printf("-1
");
}

int main ()
{
    int _case = 1;
    while ( scanf("%d%d", &n, &m) != EOF )
    {
        memset( digit, 0, sizeof(digit) );
        while ( m-- )
        {
            int tmp;
            scanf("%d", &tmp);
            digit[tmp] = 1;
        }
        printf("Case %d: ", _case++);
        bfs();
    }
    return 0;
}