地址:http://acm.hdu.edu.cn/showproblem.php?pid=1728
2 5 5 ...** *.**. ..... ..... *.... 1 1 1 1 3 5 5 ...** *.**. ..... ..... *.... 2 1 1 1 3
no yes
BFS模板题
代码:
#include <iostream> #include <cstdio> #include <cstring> #include <string> #include <queue> using namespace std; struct point { int x; int y; int step; }p, pp; #define N 150 int m, n; int k, x1, x2, y_1, y2; int sign[N][N]; int d[4][2] = { { 1, 0 }, { -1, 0 }, { 0, 1 }, { 0, -1 } }; char map[N][N]; queue<point> all; bool ok(int x, int y) { if (x >= 1 && x <= m&&y >= 1 && y <= n&&map[x][y] == '.') return true; return false; } bool bfs() { if (x1 == x2&&y_1 == y2) return true; sign[x1][y_1] = 1; p.x = x1, p.y = y_1, p.step = -1; all.push(p); while (!all.empty()) { p = all.front(); all.pop(); for (int i = 0; i < 4; i++){ int xx = p.x + d[i][0]; int yy = p.y + d[i][1]; while (ok(xx, yy)) { if (!sign[xx][yy]){ sign[xx][yy] = 1; pp.x = xx, pp.y = yy, pp.step = p.step + 1; all.push(pp); if (pp.step <= k&&pp.x == x2&&pp.y == y2) return true; } xx += d[i][0]; yy += d[i][1]; } } } return false; } int main() { int t; scanf("%d", &t); while (t--) { scanf("%d%d", &m, &n); memset(sign, 0, sizeof(sign)); while (!all.empty()) all.pop(); // 队的初始化 for (int i = 1; i <= m; i++) for (int j = 1; j <= n; j++) scanf(" %c", &map[i][j]); scanf("%d%d%d%d%d", &k, &y_1, &x1, &y2, &x2); //注意输入数据的顺序,表示没看清题别这里坑了.. if (bfs()) puts("yes"); else puts("no"); } return 0; }