two sum solved

Author: mintheon

two-sum/mintheon.java

@@ -2,25 +2,19 @@
 import java.util.Map;
 
 class Solution {
-  /**
-   공간복잡도: O(n)
-   시간복잡도: O(n)
-   */
-
   public int[] twoSum(int[] nums, int target) {
-    Map<Integer, Integer> numMap = new HashMap<>();
+    Map<Integer, Integer> indexMap = new HashMap<>();
 
     for(int i = 0; i < nums.length; i++) {
-      numMap.put(nums[i], i);
-    }
+      int remain = target - nums[i];
 
-    for(int i = 0; i < nums.length; i++) {
-      int pairNum = target - nums[i];
-      if(numMap.containsKey(pairNum) && numMap.get(pairNum) != i) {
-        return new int[]{i, numMap.get(target - nums[i])};
+      if(indexMap.containsKey(remain)) {
+        return new int[] {i, indexMap.get(remain)};
       }
+
+      indexMap.put(nums[i], i);
     }
 
-    return new int[2];
+    return new int[]{};
   }
-}
+}