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[LeetCode][JavaScript]Combination Sum II

时间:2015-05-27 00:50:58      阅读:371      评论:0      收藏:0      [点我收藏+]

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Combination Sum II

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.

Each number in C may only be used once in the combination.

Note:

  • All numbers (including target) will be positive integers.
  • Elements in a combination (a1, a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).
  • The solution set must not contain duplicate combinations.

 

For example, given candidate set 10,1,2,7,6,1,5 and target 8
A solution set is: 
[1, 7] 
[1, 2, 5] 
[2, 6] 
[1, 1, 6] 

https://leetcode.com/problems/combination-sum-ii/

 

 


 

 

有了上一道的基础,这道妥妥的。

http://www.cnblogs.com/Liok3187/p/4526863.html

说数字不能重复用,于是就从index + 1开始循环,但是这样会出现重复的数据。

比如例子中的[1,7]和[1,2,5],他们的1可以是第一个1也可以是第二个1。

我就粗暴地加了一个vistied变量去重...

 1 /**
 2  * @param {number[]} candidates
 3  * @param {number} target
 4  * @return {number[][]}
 5  */
 6 var combinationSum2 = function(candidates, target) {
 7     var res = [];
 8     var visited = new Set();
 9     candidates.sort(sorting);
10     bfs(0, -1, []);
11     return res;
12 
13     function bfs(sum, index, tmp){
14         var current = tmp.join(‘#‘);
15         if(visited.has(current)){
16             return;
17         }else{
18             visited.add(current);
19         }
20 
21         var newTmp = null;
22         if(sum === target){
23             newTmp = tmp.concat();
24             res.push(newTmp);
25             return;
26         }else if(sum > target || index + 1 >= candidates.length){
27             return; //pruning
28         }
29 
30         for(var i = index + 1; i < candidates.length; i++){
31             newTmp = tmp.concat();
32             newTmp.push(candidates[i]);
33             bfs(sum + candidates[i], i, newTmp);
34         }
35     }
36     function sorting(a, b){
37         if(a > b){
38             return 1;
39         }else if(a < b){
40             return -1;
41         }else{
42             return 0;
43         }
44     }
45 };

 

[LeetCode][JavaScript]Combination Sum II

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原文地址:http://www.cnblogs.com/Liok3187/p/4532064.html

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