NYOJ 迷宫寻宝（一）深搜

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=82

做这道题的时候迷迷糊糊的，，果然比较难。。最后也是没有做出来。。请教了一下学长，学长说我基础还不好。。基础果然重要，这道题是一道搜索题，我没有考虑钥匙在门后面的情况，比如aBbSAG 多亏学长指教，通过这道题对深搜的理解又加深了一步~

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

int m,n;//行 列
char e[25][25];//储存地图
int a1,b1,c1,d1,e1;//这张图中对应门的钥匙的总数量 

int startx,starty;//标记开始位置
int flag;//是否找到的标记
int book[21][21];

int a2,b2,c2,d2,e2;
//a2,b2,c2,d2,e2分别为可以找到的钥匙数量

int dfs(int x,int y)
{

    if(e[x][y]==‘G‘)//找到
    {
        flag = 1;
        return 1;
    }
    if(e[x][y]==‘X‘)//墙
        return 0;

    switch(e[x][y])
    {
        case ‘a‘:
            a2++;
            e[x][y] = ‘.‘;
            break;
        case ‘b‘:
            b2++;
            e[x][y] = ‘.‘;
            break;
        case ‘c‘:
            c2++;
            e[x][y] = ‘.‘;
            break;
        case ‘d‘:
            d2++;
            e[x][y] = ‘.‘;
            break;
        case ‘e‘:
            e2++;
            e[x][y] = ‘.‘;
            break;
        case ‘A‘:
            if(a1 != a2)
            {
                return 0;
            }
    //        e[x][y] = ‘.‘;
            break;
        case ‘B‘:
            if(b1 != b2)
            {
                return 0;
            }
            else
    //        e[x][y] = ‘.‘;
            break;
        case ‘C‘:
            if(c1 != c2)
            {
                return 0;
            }
    //        e[x][y] = ‘.‘;
            break;
        case ‘D‘:
            if(d1 != d2)
            {
                return 0;
            }
    //        e[x][y] = ‘.‘;
            break;
        case ‘E‘:
            if(e1 != e2)
            {
                return 0;
            }
    //        e[x][y] = ‘.‘;
            break;
    }

    if(x+1<=m&&flag==0&&book[x+1][y]==0)
    {
            book[x+1][y] = 1;
            dfs(x+1,y);
            book[x+1][y] = 0;
    }
    if(y+1<=n&&flag==0&&book[x][y+1]==0)
    {
        book[x][y+1] = 1;
        dfs(x,y+1);
        book[x][y+1] = 0;
    }
    if(x-1>=1&&flag==0&&book[x-1][y]==0)
    {
        book[x-1][y] = 1;
        dfs(x-1,y);
        book[x-1][y] = 0;
    }
    if(y-1>=1&&flag==0&&book[x][y-1]==0)
    {
        book[x][y-1] = 1;
        dfs(x,y-1);
        book[x][y-1] = 0;
    }
    return 0;
}

int main()
{

    char temp;
    //freopen("data.txt","r",stdin);
    while(scanf("%d %d",&m,&n)&&(m+n)!=0)
    {
        memset(book,0,sizeof(book));
        getchar();
        a2 = 0;b2 =0;c2=0;d2=0;e2=0;
        flag = 0;
        a1=0;b1=0;c1=0;d1=0;e1=0;

        for(int i=1;i<=m;i++)
        {
            for(int j=1;j<=n;j++)
            {
                while(scanf("%c",&temp)&&temp==‘ ‘);
                e[i][j] = temp;
                switch (e[i][j])
                {
                    case ‘a‘:
                        a1++;
                        break;
                    case ‘b‘:
                        b1++;
                        break;
                    case ‘c‘:
                        c1++;
                        break;
                    case ‘d‘:
                        d1++;
                        break;
                    case ‘e‘:
                        e1++;
                        break;
                    case ‘S‘:
                        startx = i;
                        starty = j;
                        break;
                }
            }
            getchar();
        }

        dfs(startx,starty);

        flag==1?cout<<"YES"<<endl:cout<<"NO"<<endl;
    }

    return 0;
}

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