Time: 9 ms (78.22%), Space: 39.2 MB (49.34%) - LeetHub

hajin-kim · hajin-kim · commit dd706efb870b · 2024-12-22T10:00:38.000+09:00
diff --git a/0046-permutations/0046-permutations.kt b/0046-permutations/0046-permutations.kt
@@ -6,7 +6,7 @@ class Solution {
         current: MutableList<Int>,
     ) {
         if (current.size == nums.size) {
-            result += current
+            result += current.toMutableList()
             return
         }
         for (i in nums.indices) {
@@ -15,9 +15,9 @@ class Solution {
             }
 
             used[i] = true
-            val next = current.toMutableList()
-            next += nums[i]
-            backtrack(nums, result, used, next)
+            current += nums[i]
+            backtrack(nums, result, used, current)
+            current.removeLast()
             used[i] = false
         }
     }

Original file line number	Diff line number	Diff line change
`@@ -6,7 +6,7 @@ class Solution {`
`6`	`6`	`current: MutableList<Int>,`
`7`	`7`	`) {`
`8`	`8`	`if (current.size == nums.size) {`
`9`		`- result += current`
	`9`	`+ result += current.toMutableList()`
`10`	`10`	`return`
`11`	`11`	`}`
`12`	`12`	`for (i in nums.indices) {`
`@@ -15,9 +15,9 @@ class Solution {`
`15`	`15`	`}`
`16`	`16`
`17`	`17`	`used[i] = true`
`18`		`- val next = current.toMutableList()`
`19`		`- next += nums[i]`
`20`		`- backtrack(nums, result, used, next)`
	`18`	`+ current += nums[i]`
	`19`	`+ backtrack(nums, result, used, current)`
	`20`	`+ current.removeLast()`
`21`	`21`	`used[i] = false`
`22`	`22`	`}`
`23`	`23`	`}`