题目链接在这里：

https://acm.bnu.edu.cn/bnuoj/...

从网上看的题解都是BFS的，自己写了一个DFS的，总是不对，不知何故，请高手赐教！谢谢了！！

#include #include #include #include using namespace std; int t, m, n; int map[205][205]; int mark[205][205]; int go[4][2] = { 0,1, 0,-1, 1,0, -1,0 }; void DFS(int a, int b) { for (int i = 0; i < 4; i++) { int aa = a + go[i][0]; int bb = b + go[i][1]; if (aa<1 || aa>m || bb<1 || bb>n) continue; if (mark[aa][bb] == 1) { map[aa][bb] = max(map[aa][bb], map[a][b]); continue; } if (map[aa][bb] <= map[a][b]) { mark[aa][bb] = 1; map[aa][bb] = map[a][b]; DFS(aa, bb); } } } int main() { while (scanf("%d", &t) != EOF) { while (t--) { scanf("%d%d", &m, &n); for (int i = 1; i <= m; i++) for (int j = 1; j <= n; j++) scanf("%d", &map[i][j]); int mm, nn; scanf("%d%d", &mm, &nn); int x; scanf("%d", &x); memset(mark, 0, sizeof(mark)); while (x--) { int a, b; scanf("%d%d", &a, &b); mark[a][b] = 1; DFS(a, b); } if (mark[mm][nn] == 1) puts("Yes"); else puts("No"); } } return 0; }

然后我又写了一个BFS，还是不对

#include #include #include #include #include using namespace std; struct state { int x, y; }; int go[4][2]= { 0,1, 0,-1, 1,0, -1,0 }; int map[205][205]; int mark[205][205]; int m, n; queue q; bool BFS(int x, int y) { while (!q.empty()) { state s = q.front(); q.pop(); for (int i = 0; i < 4; i++) { int xx = s.x + go[i][0]; int yy = s.y + go[i][1]; if (xx<1 || xx>m || yy<1 || yy>n) continue; if (mark[xx][yy] == 1) continue; if (map[xx][yy] > map[s.x][s.y]) continue; state tmp; tmp.x = xx; tmp.y = yy; mark[xx][yy] = 1; q.push(tmp); if (xx == x && yy == y) return true; } } return false; } int main() { int t; //freopen("my.in", "r", stdin); while (scanf("%d", &t) != EOF) { while (t--) { scanf("%d%d", &m, &n); for (int i = 1; i <= m; i++) for (int j = 1; j <= n; j++) scanf("%d", &map[i][j]); int mm, nn; scanf("%d%d", &mm, &nn); int x; scanf("%d", &x); memset(mark, 0, sizeof(mark)); while (!q.empty()) q.pop(); while (x--) { int a, b; scanf("%d%d", &a, &b); mark[a][b] = 1; state s; s.x = a; s.y = b; q.push(s); } if (BFS(mm,nn)) puts("Yes"); else puts("No"); } } return 0; }

DFS BFS都错，，我也太渣了，请高手赐教！！