day 7

Author: sachuverma

Diff for: Leetcode Daily Challenge/July-2021/07. Kth Smallest Element in a Sorted Matrix.cpp

@@ -0,0 +1,54 @@
+/*
+Kth Smallest Element in a Sorted Matrix
+========================================
+
+Given an n x n matrix where each of the rows and columns are sorted in ascending order, return the kth smallest element in the matrix.
+
+Note that it is the kth smallest element in the sorted order, not the kth distinct element.
+
+Example 1:
+Input: matrix = [[1,5,9],[10,11,13],[12,13,15]], k = 8
+Output: 13
+Explanation: The elements in the matrix are [1,5,9,10,11,12,13,13,15], and the 8th smallest number is 13
+
+Example 2:
+Input: matrix = [[-5]], k = 1
+Output: -5
+
+Constraints:
+n == matrix.length
+n == matrix[i].length
+1 <= n <= 300
+-109 <= matrix[i][j] <= 109
+All the rows and columns of matrix are guaranteed to be sorted in non-decreasing order.
+1 <= k <= n2
+*/
+
+class Solution
+{
+public:
+  int kthSmallest(vector<vector<int>> &A, int k)
+  {
+    int n = A.size(), m = A[0].size();
+    int l = A[0][0], h = A[n - 1][m - 1], ans;
+
+    while (l < h)
+    {
+      int mid = (l + h) / 2;
+      int count = 0, j = m - 1;
+
+      for (int i = 0; i < n; ++i)
+      {
+        while (j >= 0 && A[i][j] > mid)
+          j--;
+        count += j + 1;
+      }
+
+      if (count < k)
+        l = mid + 1;
+      else
+        h = mid;
+    }
+    return l;
+  }
+};

Diff for: Leetcode Daily Challenge/July-2021/README.md

@@ -1,9 +1,10 @@
 # June 2021 LeetCoding Challenge
 
-| Day | Question Links                                                                                                                                 |                         Solutions                          |
-| :-: | :--------------------------------------------------------------------------------------------------------------------------------------------- | :--------------------------------------------------------: |
-| 1.  | [Gray Code](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3799/)                     |               [cpp](./01.%20Gray%20Code.cpp)               |
-| 2.  | [Find K Closest Elements](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3800/)       |      [cpp](./02.%20Find%20K%20Closest%20Elements.cpp)      |
-| 4.  | [Count Vowels Permutation](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3802/)      |      [cpp](./04.%20Count%20Vowels%20Permutation.cpp)       |
-| 5.  | [Reshape the Matrix](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3803/)            |         [cpp](./05.%20Reshape%20the%20Matrix.cpp)          |
-| 6.  | [Reduce Array Size to The Half](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3804/) | [cpp](./06.%20Reduce%20Array%20Size%20to%20The%20Half.cpp) |
+| Day | Question Links                                                                                                                                           |                               Solutions                                |
+| :-: | :------------------------------------------------------------------------------------------------------------------------------------------------------- | :--------------------------------------------------------------------: |
+| 1.  | [Gray Code](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3799/)                               |                     [cpp](./01.%20Gray%20Code.cpp)                     |
+| 2.  | [Find K Closest Elements](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3800/)                 |            [cpp](./02.%20Find%20K%20Closest%20Elements.cpp)            |
+| 4.  | [Count Vowels Permutation](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3802/)                |            [cpp](./04.%20Count%20Vowels%20Permutation.cpp)             |
+| 5.  | [Reshape the Matrix](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3803/)                      |               [cpp](./05.%20Reshape%20the%20Matrix.cpp)                |
+| 6.  | [Reduce Array Size to The Half](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3804/)           |       [cpp](./06.%20Reduce%20Array%20Size%20to%20The%20Half.cpp)       |
+| 7.  | [Kth Smallest Element in a Sorted Matrix](https://leetcode.com/explore/challenge/card/july-leetcoding-challenge-2021/608/week-1-july-1st-july-7th/3805/) | [cpp](./07.%20Kth%20Smallest%20Element%20in%20a%20Sorted%20Matrix.cpp) |