#include<iostream>
using namespace std;
#define MAX_N 22

int map[MAX_N][MAX_N];
int answer, sign;
int R, C;

void dfs(int row, int col, int step)
{
	cout << row << " " << col << endl;
	//cout << step << endl;
	int i, j, dir;
	if(row <= 0 || row > R || col <= 0 || col > C || step > 10)
		return ;
	if(map[row][col] == 3) {
		sign = 1;
		answer = step;
		return ;
	}
	for(dir = 1; dir <= 4; dir ++) {   //dir代表4个方向
		if(dir == 1) {
			for(i = row; i > 0; i --) {
				if(map[i][col] == 3) {
					sign = 1;
					answer = step + 1;
					return ;
				}
				if(map[i][col] == 1) {
					map[i][col] = 0;
					dfs(i + 1, col, step + 1);
					map[i][col] = 1;     //回溯
					step --;
					break;              //忘break了.....
				}
			}
			if(i <= 0)
				continue;
			if(step > 10)
				return ;
		}
		if(dir == 2) {
			for(j = col; j > 0; j --) {
				if(map[row][j] == 3) {
					sign = 1;
					answer = step + 1;
					return ;
				}
				if(map[row][j] == 1) {
					map[row][j] = 0;
					dfs(row, j + 1, step + 1);
					map[row][j] = 1;
					step --;
					break;
				}
			}
			if(j <= 0)
				continue;
			if(step > 10)
				return ;
		}
		if(dir == 3) {
			for(i = row; i <= R; i ++) {
				if(map[i][col] == 3) {
					sign = 1;
					answer = step + 1;
					return ;
				}
				if(map[i][col] == 1) {
					map[i][col] = 0;
					dfs(i - 1, col, step + 1);
					map[i][col] = 1;     
					step --;
					break;
				}
			}
			if(i > R)
				continue;
			if(step > 10)
				return ;
		}
		if(dir == 4) {
			for(j = col; j <= C; j ++) {
				if(map[row][j] == 3) {
					sign = 1;
					answer = step + 1;
					return ;
				}
				if(map[row][j] == 1) {
					map[row][j] = 0;
					dfs(row, j - 1, step + 1);
					map[row][j] = 1;
					step --;
					break;
				}
			}
			if(j > C)
				continue;
			if(step > 10)
				return ;
		}
	}
	return ;
}

int main()
{
	int i, j;
	while(cin >> C >> R && C) {
		memset(map, 0, sizeof(map));
		answer = -1;
		sign = 0;
		for(i = 1; i <= R; i ++)
			for(j = 1; j <= C; j ++)
				cin >> map[i][j];
		for(i = 1; i <= R; i ++)
			for(j = 1; j <= C; j ++)
				if(map[i][j] == 2) {
					dfs(i, j, 0);
					break;
				}
		if(sign == 1)
			cout << answer << endl;
		else
			cout << -1 << endl;
	}
	return 0;
}

• Re:纠结啊。。。。。改不来了。。。。牛哥们帮忙看看 (2744) 4053040 2010-03-07 09:28:13