Two-Pointers-2

MergeSortedArray.java

@@ -0,0 +1,29 @@
+// https://leetcode.com/problems/merge-sorted-array/description
+// Time complexity : O(m+n) where m is number of elements in num1 and n is number of elements in num2
+// Space complexity : O(1)
+// Did this code successfully run on Leetcode : yes
+class Solution {
+    public void merge(int[] nums1, int m, int[] nums2, int n) {
+        int i = m-1;
+        int j = n-1;
+        int k = m+n-1;
+        while(i>=0 && j>=0){
+            int val1 = nums1[i];
+            int val2 = nums2[j];
+            if(val1>val2){
+                nums1[k] = val1;
+                i--;
+                k--;
+            }else{
+                nums1[k] = val2;
+                j--;
+                k--;
+            }
+        }
+        while(j>=0){
+            nums1[k] = nums2[j];
+            j--;
+            k--;
+        }
+    }
+}

Sample.java

@@ -5,3 +5,30 @@
 // Three line explanation of solution in plain english
 
 // Your code here along with comments explaining your approach
+// https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/
+// Time complexity :O(n)
+// Space complexity : O(1)
+// Did this code successfully run on Leetcode : yes
+class Solution {
+
+    public int removeDuplicates(int[] nums) {
+        int i = 1;
+        int count = 1;
+        int j = 1;
+        while(j<nums.length){
+            if(nums[j]==nums[j-1]){
+                count++;
+                if(count>2){
+                    j++;
+                    continue;
+                }
+            }else{
+                count = 1;
+            }
+            nums[i] = nums[j];
+            i++;
+            j++;
+        }
+        return i;
+    }
+}

Search2DMatrix.java

@@ -0,0 +1,21 @@
+// https://leetcode.com/problems/search-a-2d-matrix-ii/
+// Time complexity : O(m+n) where m is number of rows and n is number of columns
+// Space complexity : O(1)
+// Did this code successfully run on Leetcode : yes
+class Solution {
+    public boolean searchMatrix(int[][] matrix, int target) {
+        int row = matrix.length;
+        int col = matrix[0].length;
+        int i = 0;
+        int j = col-1;
+        while(i<=row-1 && j>=0){
+           if(matrix[i][j]==target) return true;
+           else if(matrix[i][j]>target){
+              j--;
+           }else{
+              i++;
+           }
+        }
+        return false;
+    }
+}