fix two some

Author: dylan-jung

two-sum/dylan-jung.cpp

@@ -1,17 +1,16 @@
+// TC: O(N), SC: O(N)
+
 class Solution {
 public:
     vector<int> twoSum(vector<int>& nums, int target) {
-        vector<tuple<int, int>> arr;
-        arr.reserve(nums.size());
+        unordered_map<int, int> m;
         for(int i = 0; i < nums.size(); i++) {
-            arr.push_back({nums[i], i});
+            m[nums[i]] = i;
         }
-        int s = 0; int e = nums.size()-1;
-        sort(arr.begin(), arr.end());
-        while(s < e) {
-            if(get<0>(arr[s]) + get<0>(arr[e]) > target) e-=1;
-            else if (get<0>(arr[s]) + get<0>(arr[e]) < target) s+=1;
-            else return {get<1>(arr[s]), get<1>(arr[e])};
+        for(int first = 0; first < nums.size(); first++) {
+            if(m.count(target - nums[first]) > 0 && first != m[target - nums[first]]) {
+                return {first, m[target - nums[first]]};
+            }
         }
         return {};
     }