refactor 46

fishercoder1534 · fishercoder1534 · commit 9a910a2329e4 · 2020-02-24T09:24:27.000-05:00
diff --git a/src/main/java/com/fishercoder/solutions/_46.java b/src/main/java/com/fishercoder/solutions/_46.java
@@ -27,24 +27,23 @@ public static class Solution1 {
         public List<List<Integer>> permute(int[] nums) {
             List<List<Integer>> result = new ArrayList();
             result.add(new ArrayList<>());
-            return backtracking(result, nums, 0);
+            return backtracking(nums, 0, result);
         }
 
-        private List<List<Integer>> backtracking(List<List<Integer>> result, int[] nums, int pos) {
-            if (pos == nums.length) {
+        private List<List<Integer>> backtracking(int[] nums, int index, List<List<Integer>> result) {
+            if (index == nums.length) {
                 return result;
             }
-            List<List<Integer>> newResult = new ArrayList();
+            List<List<Integer>> newResult = new ArrayList<>();
             for (List<Integer> eachList : result) {
                 for (int i = 0; i <= eachList.size(); i++) {
-                    //attn: i starts from 0
-                    List<Integer> newList = new ArrayList(eachList);
-                    newList.add(i, nums[pos]);
+                    List<Integer> newList = new ArrayList<>(eachList);
+                    newList.add(i, nums[index]);
                     newResult.add(newList);
                 }
             }
             result = newResult;
-            return backtracking(result, nums, pos + 1);
+            return backtracking(nums, index + 1, result);
         }
     }
 

Original file line number	Diff line number	Diff line change
`@@ -27,24 +27,23 @@ public static class Solution1 {`
`27`	`27`	`public List<List<Integer>> permute(int[] nums) {`
`28`	`28`	`List<List<Integer>> result = new ArrayList();`
`29`	`29`	`result.add(new ArrayList<>());`
`30`		`- return backtracking(result, nums, 0);`
	`30`	`+ return backtracking(nums, 0, result);`
`31`	`31`	`}`
`32`	`32`
`33`		`- private List<List<Integer>> backtracking(List<List<Integer>> result, int[] nums, int pos) {`
`34`		`- if (pos == nums.length) {`
	`33`	`+ private List<List<Integer>> backtracking(int[] nums, int index, List<List<Integer>> result) {`
	`34`	`+ if (index == nums.length) {`
`35`	`35`	`return result;`
`36`	`36`	`}`
`37`		`- List<List<Integer>> newResult = new ArrayList();`
	`37`	`+ List<List<Integer>> newResult = new ArrayList<>();`
`38`	`38`	`for (List<Integer> eachList : result) {`
`39`	`39`	`for (int i = 0; i <= eachList.size(); i++) {`
`40`		`- //attn: i starts from 0`
`41`		`- List<Integer> newList = new ArrayList(eachList);`
`42`		`- newList.add(i, nums[pos]);`
	`40`	`+ List<Integer> newList = new ArrayList<>(eachList);`
	`41`	`+ newList.add(i, nums[index]);`
`43`	`42`	`newResult.add(newList);`
`44`	`43`	`}`
`45`	`44`	`}`
`46`	`45`	`result = newResult;`
`47`		`- return backtracking(result, nums, pos + 1);`
	`46`	`+ return backtracking(nums, index + 1, result);`
`48`	`47`	`}`
`49`	`48`	`}`
`50`	`49`