zoj 2110 骨头的诱惑(Tempter of the Bone) DFS

地址  https://vjudge.net/problem/ZOJ-2110

 

 

 

初始看就是个简单的DFS 或者BFS

后来卡了半天 才发现 是恰好T秒达到.......

做了剪枝 修改了成功退出的判断条件为 == T 然后ac了

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <memory.h>


using namespace std;

int n, m, t;

const int MAX_SIZE = 90;

char G[MAX_SIZE][MAX_SIZE];

int currx, curry;

int addx[] = { 0,0,1,-1 };
int addy[] = { 1,-1,0,0 };

int endX;
int endY;



int Dfs(int x, int y, int limit)
{
    int count = 0;

    if (x < 0 || x >= n || y < 0 || y >= m) {
        return 0;
    }
    if (G[x][y] == 'X')
        return 0;
    if (G[x][y] == 'D' && limit == t)
        return 1;
    if (limit > t)
        return 0;

    int temp = (t - limit) - abs(x - endX) - abs(y - endY);
    
    if (temp < 0 )
        return 0;


    for (int i = 0; i < 4; i++) {
        int newx = addx[i] + x;
        int newy = addy[i] + y;
        char oldV = G[x][y];
        G[x][y] = 'X';
        if (Dfs(newx, newy, limit + 1) == 1)
            return 1;
        G[x][y] = oldV;
    }

    return 0;
}


int main()
{
    while (scanf("%d%d%d", &n, &m, &t)) {
        if (n == m && m== t && t == 0) 
            break;

        memset(G, 0, sizeof G);

        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++) {
                cin >> G[i][j];
                if (G[i][j] == 'S') {
                    currx = i;
                    curry = j;
                }
                else if (G[i][j] == 'D') {
                    endX = i;
                    endY = j;
                }
            }
        if (Dfs(currx, curry, 0) != 0)
            printf("YES\n");
        else
            printf("NO\n"); 
    }

    return 0;
}