June19: DP practicing [H]

Time: O(mnlog(mn)), Space: O(mn)

daily/June19.cpp

@@ -0,0 +1,39 @@
+#include <bits/stdc++.h>
+
+#include <algorithm>
+using namespace std;
+
+class Solution {
+ public:
+  /**
+   * @brief LC: 2173: Maximum Strictly Increasing Cells in a Matrix
+   * DP
+   * Time: O(mnlog(mn)), Space: O(mn)
+   *
+   * @param mat
+   * @return int
+   */
+  int maxIncreasingCells(vector<vector<int>>& mat) {
+    int m = mat.size(), n = mat[0].size();
+    map<int, vector<pair<int, int>>> g;
+    for (int i = 0; i < m; i++) {
+      for (int j = 0; j < n; j++) {
+        g[mat[i][j]].emplace_back(i, j);  // same ele same group
+      }
+    }
+
+    vector<int> row_max(m), col_max(n);
+    for (auto& [_, pos] : g) {
+      vector<int> mx;  // get max, update row_max / col_max
+      for (auto& [i, j] : pos) {
+        mx.push_back(max(row_max[i], col_max[j]) + 1);
+      }
+      for (int k = 0; k < pos.size(); k++) {
+        auto& [i, j] = pos[k];
+        row_max[i] = max(row_max[i], mx[k]);  // update row i max f
+        col_max[j] = max(col_max[j], mx[k]);  // update col j max f
+      }
+    }
+    return *max_element(row_max.begin(), row_max.end());
+  }
+};