Merge pull request ignacio-chiazzo#30 from ignacio-chiazzo/prob

Added set mattrix zeroes

Author: ignacio-chiazzo

LeetcodeProblems/Set_Matrix_Zeroes.js

@@ -0,0 +1,113 @@
+/*
+Set Matrix Zeroes
+https://leetcode.com/problems/set-matrix-zeroes/
+
+Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place.
+
+Example 1:
+
+Input: 
+[
+  [1,1,1],
+  [1,0,1],
+  [1,1,1]
+]
+Output: 
+[
+  [1,0,1],
+  [0,0,0],
+  [1,0,1]
+]
+Example 2:
+
+Input: 
+[
+  [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]
+]
+Follow up:
+
+A straight forward 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?
+*/
+
+/**
+ * @param {number[][]} matrix
+ * @return {void} Do not return anything, modify matrix in-place instead.
+ */
+var setZeroes = function(matrix) {
+  if(matrix.length === 0)
+      return;
+  
+  var pivotRow = -1;
+  var pivotCol = -1;
+  var iterRow = 0;
+  var iterCol = 0;
+  var found = false;
+  
+  // Find a pivot
+  while(!found && iterRow < matrix.length) {
+    iterCol = 0;
+    while(!found && iterCol < matrix[0].length) {
+      if(matrix[iterRow][iterCol] === 0) {
+        found = true
+        pivotRow = iterRow;
+        pivotCol = iterCol;
+      }
+      iterCol++;
+    }
+    iterRow++;
+  }
+  
+  if (!found)
+    return;
+  
+  // Update the Column value
+  for(var i = 0; i < matrix.length; i++) {
+    if(i == pivotRow)
+      continue
+    for(var j = 0; j < matrix[0].length; j++) {
+      if(j == pivotCol)
+        continue;
+      if(matrix[i][j] === 0) {
+        matrix[i][pivotCol] = 0;
+        matrix[pivotRow][j] = 0;
+      }
+    }
+  }
+  
+  for(var i = 0; i < matrix.length; i++)
+    if(matrix[i][pivotCol] === 0 && i !== pivotRow)
+      fillRow(matrix, i);
+  
+  for(var i = 0; i < matrix[0].length; i++)
+    if(matrix[pivotRow][i] === 0 && i !== pivotCol)
+      fillCol(matrix, i);
+  
+  fillCol(matrix, pivotCol);
+  fillRow(matrix, pivotRow);
+};
+
+var fillRow = function(matrix, row) {
+  for(var i = 0; i < matrix[0].length; i++)
+      matrix[row][i] = 0;
+}
+
+var fillCol = function(matrix, col) {
+  for(var i = 0; i < matrix.length; i++)
+    matrix[i][col] = 0;
+}
+
+var main = function() {
+  console.log(setZeroes([[1,1,1],[1,0,1],[1,1,1]]));
+}
+
+module.exports.main = main;

README.md

@@ -6,6 +6,7 @@ Solutions of algorithm problems using Javascript
 
 | Name | Level | Link | 
 | - | - | - |
+| [Set Matrix Zeroes](/LeetcodeProblems/Set_Matrix_Zeroes.js)                                          | Hard   | https://leetcode.com/problems/set-matrix-zeroes/ |
 | [Edit Distance ](/LeetcodeProblems/Edit_Distance.js)                                                 | Hard   | https://leetcode.com/problems/edit-distance/ |
 | [Remove Invalid Parentheses ](/LeetcodeProblems/Remove_Invalid_Parentheses.js)                       | Hard   | https://leetcode.com/problems/remove-invalid-parentheses/ |
 | [Longest Consecutive Sequence ](/LeetcodeProblems/Longest_Consecutive_Sequence.js)                   | Hard   | https://leetcode.com/problems/longest-consecutive-sequence/ |