feat : set-matrix-zeroes

Author: ekgns33

set-matrix-zeroes/ekgns33.java

@@ -0,0 +1,59 @@
+/**
+
+ sol1 ) brute force
+ save zero points, replace row
+
+ read O(mn)
+ save zero points
+ replace row,cols
+ tc : O(mn)
+ sc : O(mn)
+
+ sol2) use bitwise
+ length of matrix < integer range
+ use bit wise
+ tc : O(mn)
+ sc : O(m + n)
+
+ sol3) use first row, col as memo
+ read matrix, check to row or col if zero
+
+ replace if row, col is marked as zero
+ tc : O(mn)
+ sc : O(1) in-place
+ */
+class Solution {
+  public void setZeroes(int[][] matrix) {
+    int m = matrix.length;
+    int n = matrix[0].length;
+    boolean firstRowZero = false;
+    boolean firstColZero = false;
+    for(int i = 0; i < m; i++) {
+      for(int j = 0; j < n; j++) {
+        if(matrix[i][j] == 0) {
+          if(i == 0) firstRowZero = true;
+          if(j == 0) firstColZero = true;
+          matrix[i][0] = 0;
+          matrix[0][j] = 0;
+        }
+      }
+    }
+    for(int i = 1; i <m; i++) {
+      for(int j = 1; j < n; j++) {
+        if(matrix[i][0] == 0 || matrix[0][j] == 0) {
+          matrix[i][j] = 0;
+        }
+      }
+    }
+    if(firstRowZero) {
+      Arrays.fill(matrix[0], 0);
+    }
+    if(firstColZero) {
+      for(int j = 0; j <m; j++) {
+        matrix[j][0] = 0;
+      }
+    }
+
+
+  }
+}