add solution of problem 73: set matrix zeroes

Author: ppulse

SetMatrixZeroes73/README.md

@@ -0,0 +1 @@
+Given a *m* x *n* matrix, if an element is 0, set its entire row and column to 0. Do it in place.

SetMatrixZeroes73/Solution.java

@@ -0,0 +1,31 @@
+public class Solution {
+    class Index {
+        public final int first;
+        public final int second;
+        public Index(int first, int second) {
+            this.first = first;
+            this.second = second;
+        }
+    }
+    
+    public void setZeroes(int[][] matrix) {
+        if (matrix == null || matrix.length == 0 || matrix[0].length == 0)
+            return;
+        
+        List<Index> indexList = new ArrayList<Index>();
+        for (int i = 0; i < matrix.length; i++) {
+            for (int j = 0; j < matrix[i].length; j++) {
+                if (matrix[i][j] == 0)
+                    indexList.add(new Index(i, j)); 
+            }
+        }
+
+        for (Index idx : indexList) {
+            for (int i = 0; i < matrix[0].length; i++)
+                matrix[idx.first][i] = 0;
+            
+            for (int i = 0; i < matrix.length; i++)
+                matrix[i][idx.second] = 0;
+        }
+    }
+}