day 13

Author: sachuverma

Leetcode Daily Challenge/August-2021/13. Set Matrix Zeroes.cpp

@@ -0,0 +1,80 @@
+/*
+Set Matrix Zeroes
+=================
+
+Given an m x n integer matrix matrix, if an element is 0, set its entire row and column to 0's, and return the matrix.
+
+You must do it in place.
+
+Example 1:
+Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]
+Output: [[1,0,1],[0,0,0],[1,0,1]]
+
+Example 2:
+Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]]
+Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]
+ 
+Constraints:
+m == matrix.length
+n == matrix[0].length
+1 <= m, n <= 200
+-231 <= matrix[i][j] <= 231 - 1
+ 
+Follow up:
+A straightforward solution using O(mn) space is probably a bad idea.
+A simple improvement uses O(m + n) space, but still not the best solution.
+Could you devise a constant space solution?
+*/
+
+class Solution {
+public:
+    void setZeroes(vector<vector<int>>& A) {
+        int row = 1, col = 1;
+        int n = A.size(), m = A[0].size();
+        
+        for(int i = 0; i < n; ++i) {
+            for(int j = 0; j < m; ++j) {
+                if(A[i][j] == 0) {
+                    
+                    if(i == 0) row = 0;
+                    if(j == 0) col = 0;
+                    
+                    if(i != 0 || j != 0) {
+                        if(j != 0) A[0][j] = 0;
+                        if(i != 0) A[i][0] = 0;
+                    }
+                    
+                }
+            }
+        }
+        
+        for(int i = 1; i < n; ++i) {
+            if(A[i][0] == 0) {
+                for(int j = 0; j < m; ++j) {
+                    A[i][j] = 0;
+                }
+            }
+        }
+        
+        for(int j = 1; j < m; ++j) {
+            if(A[0][j] == 0) {
+                for(int i = 0; i < n; ++i) {
+                    A[i][j] = 0;
+                }
+            }
+        }
+        
+        if(row == 0) {
+            for(int j = 0; j < m; ++j) {
+                A[0][j] = 0;
+            }
+        }
+        
+        if(col == 0) {
+            for(int i = 0; i < n; ++i) {
+                A[i][0] = 0;
+            }
+        }
+    }
+};
+

Leetcode Daily Challenge/August-2021/README.md

@@ -15,3 +15,4 @@
 | 10. | [Flip String to Monotone Increasing](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3876/)      |  [cpp](./10.%20Flip%20String%20to%20Monotone%20Increasing.cpp)  |
 | 11. | [Array of Doubled Pairs](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3877/)                  |         [cpp](./11.%20Array%20of%20Doubled%20Pairs.cpp)         |
 | 12. | [Group Anagrams](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3887/)                          |               [cpp](./12.%20Group%20Anagrams.cpp)               |
+| 13. | [Set Matrix Zeroes](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/614/week-2-august-8th-august-14th/3888/)                          |               [cpp](./13.%20Set%20Matrix%20Zeroes.cpp)               |