I have added the question- Two sum along with the solution

leet_code_problems/Two sum

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+PROBLEM STATEMENT-
+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]
+Output: 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.
+
+
+Solution- This is the c++ solution
+class Solution {
+public:
+    vector<int> twoSum(vector<int>& nums, int target) {
+        int n=nums.size();
+        int i=0,j=0;
+        vector <int> ret;
+        for(i=0;i<n-1;i++){
+for(j=i+1;j<n;j++){
+    if(nums[i]+nums[j]== target){
+ret.push_back(i);
+ret.push_back(j);
+return ret;
+}
+}
+}
+            return ret;
+    }
+};