const int N = 210;
class Solution {
public:
int f[N][N];
int ans = 1, n, m;
int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
vector<vector<int>> g;
int longestIncreasingPath(vector<vector<int>>& matrix) {
memset(f, -1, sizeof f);
g = matrix;
n = matrix.size(), m = matrix[0].size();
for (int i = 0; i < n; i ++ )
for (int j = 0; j < m; j ++ )
ans = max(ans, dfs(i, j));
return ans;
}
int dfs(int x, int y) {
int& v = f[x][y];
if (v != -1) return v;
int res = 1;
for (int i = 0; i < 4; i ++ ) {
int a = x + dx[i], b = y + dy[i];
if (a >= 0 && a < n && b >= 0 && b < m && g[a][b] < g[x][y])
res = max(res, dfs(a, b) + 1);
}
return v = res;
}
};