@[_NOCl_](/user/1054699)
```cpp
#include<iostream>
#include<algorithm>
using namespace std;
int rows, cols;
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };
int squ[101][101] = { {0} };
int store[101][101] = { {0} };
int dfs(int x, int y) {
if (store[x][y] != 0) return store[x][y];
store[x][y]=1;
for (int i = 0; i < 4; i++) {
int tx = x + dx[i];
int ty = y + dy[i];
if (tx >= 0 && ty >= 0 && tx < rows && ty < cols) {
if (squ[x][y] > squ[tx][ty]) {
dfs(tx, ty);
store[x][y] = max(store[x][y], store[tx][ty] + 1);
}
}
}
return store[x][y];
}
int main() {
cin >> rows >> cols;
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
cin >> squ[i][j];
}
}
int ans = 0;
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
ans = max(dfs(i, j), ans);
}
}
cout << ans ;
}
```
by BugGod @ 2023-09-02 14:35:32
@[_NOCl_](/user/1054699) 你的dfs判断里r和c写反了，而且你下标从0开始，应该是小于而不是小于等于
by BugGod @ 2023-09-02 14:37:29
@[Quantum_Graph](/user/541254)
谢谢帮助，但是这个是范围问题，
```cpp
store[x][y]//记忆化搜索，而不是判断是否使用过
```
改变了一下搜索的范围
```
#include<iostream>
#include<algorithm>
using namespace std;
int rows, cols;
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };
int squ[105][105] = { {0} };
int store[105][105] = { {0} };
int dfs(int x, int y) {
if (store[x][y] != 0) return store[x][y];
for (int i = 0; i < 4; i++) {
int tx = x + dx[i];
int ty = y + dy[i];
if (tx > 0 && ty > 0 && tx <= rows && ty <= cols) {
if (squ[x][y] > squ[tx][ty]) {
dfs(tx, ty);
store[x][y] = max(store[x][y], store[tx][ty] + 1);
}
}
}
return store[x][y];
}
int main() {
cin >> rows >> cols;
for (int i = 1; i <= rows; i++) {
for (int j = 1; j <= cols; j++) {
cin >> squ[i][j];
}
}
int ans = 0;
for (int i = 1; i <= rows; i++) {
for (int j = 1; j <= cols; j++) {
ans = max(dfs(i, j), ans);
}
}
cout << ans + 1;
}
```
这下AC过了
by _NOCl_ @ 2023-09-02 14:40:23
@[_NOCl_](/user/1054699) 不是，我的写法是把 s[x][y] 记为1（自己走向自己算一步）
by BugGod @ 2023-09-02 14:44:42
@[Quantum_Graph](/user/541254) 而不是像你一样，最后加一步。
by BugGod @ 2023-09-02 14:45:29