⚡ improve two-sum solution

dohee789 · dohee789 · commit e2a17cef8b0b · 2025-07-23T20:26:59.000+09:00
diff --git a/two-sum/dohee789.java b/two-sum/dohee789.java
@@ -6,16 +6,14 @@ public int[] twoSum(int[] nums, int target) {
         Map<Integer, Integer> map = new HashMap<>();
 
         for(int i = 0; i < nums.length; i++) {
-            map.put(nums[i], i);
-        }
-
-        for(int i = 0; i < nums.length; i++) {
-            if(map.containsKey(target - nums[i]) && map.get(target - nums[i]) != i) {
+            if(map.containsKey(target - nums[i])) {
                 int j = map.get(target - nums[i]);
                 return new int[]{i, j};
             }
+            map.put(nums[i], i);
         }
 
         return null;
     }
 }
+

Original file line number	Diff line number	Diff line change
`@@ -6,16 +6,14 @@ public int[] twoSum(int[] nums, int target) {`
`6`	`6`	`Map<Integer, Integer> map = new HashMap<>();`
`7`	`7`
`8`	`8`	`for(int i = 0; i < nums.length; i++) {`
`9`		`- map.put(nums[i], i);`
`10`		`- }`
`11`		`-`
`12`		`- for(int i = 0; i < nums.length; i++) {`
`13`		`- if(map.containsKey(target - nums[i]) && map.get(target - nums[i]) != i) {`
	`9`	`+ if(map.containsKey(target - nums[i])) {`
`14`	`10`	`int j = map.get(target - nums[i]);`
`15`	`11`	`return new int[]{i, j};`
`16`	`12`	`}`
	`13`	`+ map.put(nums[i], i);`
`17`	`14`	`}`
`18`	`15`
`19`	`16`	`return null;`
`20`	`17`	`}`
`21`	`18`	`}`
	`19`	`+`