#include <cstdio>
#include <cstring>
#include <algorithm>
#define MAX_N 205

using namespace std;

int grid[MAX_N][MAX_N], N, M, ans;

bool dfs(int x, int y, int deep, int maxDeep) {
	static const int xc[] = { 1,0,0,-1 };
	static const int yc[] = { 0,-1,1,0 };

	if (deep >= maxDeep) return false;
	for (int i = 0;i < 4;++i) {
		int nx = x, ny = y;
		while (grid[nx + xc[i]][ny + yc[i]] == 0)
			nx = nx + xc[i], ny = ny + yc[i];
		if (grid[nx + xc[i]][ny + yc[i]] == 3) return true;
		if ((grid[nx + xc[i]][ny + yc[i]] == -1) ||
			(nx == x && ny == y)) continue;
		grid[nx + xc[i]][ny + yc[i]] = 0;
		if (dfs(nx, ny, deep + 1, maxDeep)) return true;
		grid[nx + xc[i]][ny + yc[i]] = 1;
	}
	return false;
}

int main(int argc, char *argv[]) {
	while (scanf("%d%d", &M, &N) == 2 && N != 0 && M != 0) {
		int ans = -1, bx, by;
		memset(grid, -1, sizeof(grid));
		for (int i = 1;i <= N;++i)
			for (int j = 1;j <= M;++j) {
				scanf("%d", &grid[i][j]);
				if (grid[i][j] == 2) {
					bx = i, by = j;
					grid[i][j] = 0;
				}
			}
		for (int k = 1;k <= 10;++k)
			if (dfs(bx, by, 0, k)) {
				ans = k;
				break;
			}
		printf("%d\n", ans);
	}
	return 0;
}

• Re:迭代加深水过 (1312) sjdeak 2016-12-18 07:41:28