搜索与图论：宽度优先搜索
搜索与图论：宽度优先搜索
- 题目描述
- 参考代码
题目描述
输入样例
5 5
0 1 0 0 0
0 1 0 1 0
0 0 0 0 0
0 1 1 1 0
0 0 0 1 0
输出样例
8
参考代码
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;const int N = 110;typedef pair<int, int> PII;int n, m;
int g[N][N]; // 存储地图
int d[N][N]; // 每一个点到起点的距离
PII q[N * N], Prev[N][N];int bfs()
{int hh = 0, tt = 0;q[0] = {0, 0};memset(d, -1, sizeof d);d[0][0] = 0;int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};while (hh <= tt){auto t = q[hh ++];for (int i = 0; i < 4; i++){int x = t.first + dx[i], y = t.second + dy[i];if (x >= 0 && x < n && y >= 0 && y < m && g[x][y] == 0 && d[x][y] == -1){d[x][y] = d[t.first][t.second] + 1;Prev[x][y] = t;q[++ tt] = {x, y};}}}int x= n - 1, y = m - 1;while (x || y){cout << x << ' ' << y << endl;auto t = Prev[x][y];x = t.first, y = t.second;}return d[n - 1][m - 1];
}int main()
{cin >> n >> m;for (int i = 0; i < n; i++)for (int j = 0; j < m; j++)cin >> g[i][j];cout << bfs() << endl;return 0;
}