day 22

Author: sachuverma

Leetcode Daily Challenge/April-2021/22. Brick Wall.cpp

@@ -0,0 +1,67 @@
+/*
+Brick Wall
+==========
+
+There is a brick wall in front of you. The wall is rectangular and has several rows of bricks. The bricks have the same height but different width. You want to draw a vertical line from the top to the bottom and cross the least bricks.
+
+The brick wall is represented by a list of rows. Each row is a list of integers representing the width of each brick in this row from left to right.
+
+If your line go through the edge of a brick, then the brick is not considered as crossed. You need to find out how to draw the line to cross the least bricks and return the number of crossed bricks.
+
+You cannot draw a line just along one of the two vertical edges of the wall, in which case the line will obviously cross no bricks.
+
+Example:
+Input: [[1,2,2,1],
+        [3,1,2],
+        [1,3,2],
+        [2,4],
+        [3,1,2],
+        [1,3,1,1]]
+Output: 2
+
+Note:
+The width sum of bricks in different rows are the same and won't exceed INT_MAX.
+The number of bricks in each row is in range [1,10,000]. The height of wall is in range [1,10,000]. Total number of bricks of the wall won't exceed 20,000.
+*/
+
+class Solution
+{
+public:
+  int leastBricks(vector<vector<int>> &wall)
+  {
+    if (wall.size() == 1)
+    {
+      if (wall[0].size() == 1)
+        return 1;
+      return 0;
+    }
+
+    if (wall[0].size() == 1 && wall[0][0] == 1)
+      return wall.size();
+    vector<vector<int>> dp;
+
+    for (auto &row : wall)
+    {
+      vector<int> arr = {row[0]};
+      for (int i = 1; i < row.size(); ++i)
+      {
+        arr.push_back({arr[i - 1] + row[i]});
+      }
+      dp.push_back(arr);
+    }
+
+    int ans = INT_MIN;
+    unordered_map<int, int> freq;
+
+    for (auto &row : dp)
+    {
+      for (auto &i : row)
+      {
+        if (i != dp[0][dp[0].size() - 1])
+          freq[i]++;
+        ans = max(ans, freq[i]);
+      }
+    }
+    return dp.size() - ans;
+  }
+};

Leetcode Daily Challenge/April-2021/README.md

@@ -20,6 +20,7 @@
 | 16. | [Remove All Adjacent Duplicates in String II](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3710/) | [cpp](./16.%20Remove%20All%20Adjacent%20Duplicates%20in%20String%20II.cpp) |
 | 17. | [Number of Submatrices That Sum to Target](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3711/)    |  [cpp](./17.%20Number%20of%20Submatrices%20That%20Sum%20to%20Target.cpp)   |
 | 18. | [Remove Nth Node From End of List](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3712/)            |      [cpp](./18.%20Remove%20Nth%20Node%20From%20End%20of%20List.cpp)       |
-| 19. | [Combination Sum IV](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3713/)            |      [cpp](./19.%20Combination%20Sum%20IV.cpp)       |
-| 20. | [N-ary Tree Preorder Traversal](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3714/)    |  [cpp](./20.%20N-ary%20Tree%20Preorder%20Traversal.cpp)       |
-| 21. | [Triangle](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3715/)    |  [cpp](./21.%20Triangle.cpp)       |
+| 19. | [Combination Sum IV](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3713/)                          |                 [cpp](./19.%20Combination%20Sum%20IV.cpp)                  |
+| 20. | [N-ary Tree Preorder Traversal](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3714/)               |           [cpp](./20.%20N-ary%20Tree%20Preorder%20Traversal.cpp)           |
+| 21. | [Triangle](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/595/week-3-april-15th-april-21st/3715/)                                    |                        [cpp](./21.%20Triangle.cpp)                         |
+| 22. | [Brick Wall](https://leetcode.com/explore/challenge/card/april-leetcoding-challenge-2021/596/week-4-april-22nd-april-28th/3717/)                                  |                      [cpp](./22.%20Brick%20Wall.cpp)                       |