Added Two Sum Leetcode solution (dubesar#613)

Co-authored-by: Sourabh Varshney <sourabh.varshney@hotstar.com>

Author: sourabhvarshney111

LeetCode/Top 100 Liked/Two Sum/Solution.java

@@ -0,0 +1,18 @@
+import java.util.*;
+
+class Solution {
+    public int[] twoSum(int[] nums, int target) {
+        int n=nums.length;
+        Map<Integer,Integer> map=new HashMap<>();
+        int[] result=new int[2];
+        for(int i=0;i<n;i++){
+            if(map.containsKey(target-nums[i])){
+                result[1]=i;
+                result[0]=map.get(target-nums[i]);
+                return result;
+            }
+            map.put(nums[i],i);
+        }
+        return result;
+    }
+}

LeetCode/Top 100 Liked/Two Sum/problem_statement.txt

@@ -0,0 +1,29 @@
+Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
+
+You may assume that each input would have exactly one solution, and you may not use the same element twice.
+
+You can return the answer in any order.
+
+
+
+Example 1:
+
+Input: nums = [2,7,11,15], target = 9
+Output: [0,1]
+Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].
+Example 2:
+
+Input: nums = [3,2,4], target = 6
+Output: [1,2]
+Example 3:
+
+Input: nums = [3,3], target = 6
+Output: [0,1]
+
+
+Constraints:
+
+2 <= nums.length <= 104
+-109 <= nums[i] <= 109
+-109 <= target <= 109
+Only one valid answer exists.