July 5: moddify matrix [E]

use loop to traverse the matrix, easy. 2D traverse

daily/Jul5.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+ public:
+  /**
+   * @brief LC: 3033: modify the matrix [E]
+   * Time: O(N*M), Space: O(N*M)
+   *
+   * @param matrix
+   * @return vector<vector<int>>
+   */
+  vector<vector<int>> modifiedMatrix(vector<vector<int>>& matrix) {
+    vector<vector<int>> ans = matrix;
+    int row = matrix.size();
+    int col = matrix[0].size();
+    for (int i = 0; i < col; i++) {
+      int max = matrix[0][i];
+      for (int j = 0; j < row; j++) {
+        max = max > matrix[j][i] ? max : matrix[j][i];
+      }
+      for (int j = 0; j < row; j++) {
+        if (ans[j][i] == -1) {
+          ans[j][i] = max;
+        }
+      }
+    }
+    return ans;
+  }
+};

daily/June28.cpp

@@ -0,0 +1,34 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+ public:
+  /**
+   * @brief LC: 2742: Painting the walls
+   * Time & Space: O(n^2), DP: nums of state * time per state
+   *
+   * @param cost
+   * @param time
+   * @return int
+   */
+  int paintWalls(vector<int>& cost, vector<int>& time) {
+    int n = cost.size();
+    vector<vector<int>> memo(n, vector<int>(n * 2 + 1, -1));
+    auto dfs = [&](auto&& dfs, int i, int j) -> int {
+      if (j > i) {  // all walls can be painted free
+        return 0;
+      }
+      if (i < 0) {
+        // j < 0
+        return INT_MAX / 2;
+      }
+      int& res = memo[i][j + n];  // add offset
+      if (res != -1) {            // calculated before
+        return res;
+      }
+      return res = min(dfs(dfs, i - 1, j + time[i]) + cost[i],
+                       dfs(dfs, i - 1, j - 1));
+    };
+    return dfs(dfs, n - 1, 0);
+  }
+};