HDU2821 深搜 xingxing1024

　　这道题就是按照题意搜索就行， 也没啥坑的地方，代码如下：

　　

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
int n, m;   //n行 m列
int map[26][26];
char line[30];
char dir[4] = {'R', 'L', 'D', 'U'};
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
bool inside(int x, int y) 
{
    return (x>=0 && x<n && y>=0 && y<m); 
}

int now[26][26];
int judge()
{
    for(int i=0; i<n; i++)
        for(int j=0; j<m; j++)
            if(now[i][j] > 0)
                return false;
    return true;
}
int go[1000], ss;
bool flog;
void dfs(int x, int y, int steps)   //走到x, y走了 steps步
{
    //printf("x = %d, y=%d, steps = %d\n", x, y, steps);
    if(judge())
    {
        ss = steps;
        flog = true;
    }
    else 
    {
        for(int i=0; i<4&&!flog; i++)   //朝四个方向走
        {
            int nx = x, ny=y;
            while(inside(nx+dx[i], ny+dy[i]) && now[nx+dx[i]][ny+dy[i]]==0) 
                nx = nx+dx[i], ny = ny+dy[i];
            if(!inside(nx+dx[i], ny+dy[i]))
                continue;
            else if(now[nx+dx[i]][ny+dy[i]]>0 && nx==x && ny==y)
                continue;
            else if(now[nx+dx[i]][ny+dy[i]]>0 && (nx!=x || ny!=y))
            {
                go[steps] = i;
                int num = now[nx+dx[i]][ny+dy[i]];
                if(inside(nx+2*dx[i], ny+2*dy[i]))
                    now[nx+2*dx[i]][ny+2*dy[i]] += (now[nx+dx[i]][ny+dy[i]]-1);
                now[nx+dx[i]][ny+dy[i]] = 0;
                dfs(nx+dx[i], ny+dy[i], steps+1);
                now[nx+dx[i]][ny+dy[i]] = num;
                if(inside(nx+2*dx[i], ny+2*dy[i]))
                    now[nx+2*dx[i]][ny+2*dy[i]] -= (now[nx+dx[i]][ny+dy[i]]-1);
            }
        }
    }
}

int main()
{
    while(scanf("%d%d", &m, &n) == 2)
    {
        for(int i=0; i<n; i++)
        {
            scanf("%s", line);
            for(int j=0; j<m; j++)
            {
                if(line[j] == '.')
                    map[i][j] = 0;
                else 
                    map[i][j] = line[j]-'a'+1;
            }
        }
/*        for(int i=0; i<n; i++)
        {
            for(int j=0; j<m; j++)
                printf("%d ", map[i][j]);
            printf("\n");
        }*/
        bool co = false;
        int tpx, tpy;
        for(int i=0; i<n&&!co; i++)
            for(int j=0; j<m&&!co; j++) 
            {
                if(map[i][j]>0) continue;
                //printf("sx = %d, sy = %d\n\n", i, j);
                memcpy(now, map, sizeof(map));
                flog = false;
                dfs(i, j, 0);
                if(flog == true)
                {
                    co = true;
                    tpx = i; tpy = j;
                }
            }
        printf("%d\n%d\n", tpx, tpy);
        for(int i=0; i<ss; i++)
            printf("%c", dir[go[i]]);
        printf("\n");
    }
    return 0;
}