leetcode40

 1 class Solution {
 2     public List<List<Integer>> combinationSum2(int[] candidates, int target) {
 3         List<List<Integer>> combinations = new ArrayList<>();
 4         Arrays.sort(candidates);
 5         List<Integer> tempCombination = new ArrayList<>();
 6         backtracking(tempCombination, combinations, new boolean[candidates.length], 0, target, candidates);
 7         return combinations;
 8     }
 9 
10     private void backtracking(List<Integer> tempCombination, List<List<Integer>> combinations,
11                               boolean[] hasVisited, int start, int target, final int[] candidates) {
12 
13         if (target == 0) {
14             combinations.add(new ArrayList<>(tempCombination));
15             return;
16         }
17         for (int i = start; i < candidates.length; i++) {
18             if (i != 0 && candidates[i] == candidates[i - 1] && !hasVisited[i - 1]) {
19                 continue;
20             }
21             if (candidates[i] <= target) {
22                 tempCombination.add(candidates[i]);
23                 hasVisited[i] = true;
24                 backtracking(tempCombination, combinations, hasVisited, i + 1, target - candidates[i], candidates);
25                 hasVisited[i] = false;
26                 tempCombination.remove(tempCombination.size() - 1);
27             }
28         }
29     }
30 }

对比leetcode39：

 1 public class LEET_39 {
 2     public List<List<Integer>> combinationSum(int[] candidates, int target) {
 3         List<List<Integer>> combinations = new ArrayList<>();
 4         List<Integer> tempCombination = new ArrayList<>();
 5         backtracking(tempCombination, combinations, 0, target, candidates);
 6         return combinations;
 7     }
 8 
 9     private void backtracking(List<Integer> tempCombination, List<List<Integer>> combinations,
10                               int start, int target, final int[] candidates) {
11 
12         if (target == 0) {
13             combinations.add(new ArrayList<>(tempCombination));
14             return;
15         }
16         for (int i = start; i < candidates.length; i++) {
17             if (candidates[i] <= target) {
18                 tempCombination.add(candidates[i]);
19                 backtracking(tempCombination, combinations, i, target - candidates[i], candidates);
20                 tempCombination.remove(tempCombination.size() - 1);
21             }
22         }
23     }
24 }

posted on 2019-06-10 15:35 Sempron2800+ 阅读(216) 评论(0) 编辑收藏举报