标签：
Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers.
Ensure that numbers within the set are sorted in ascending order.
Example 1:
Input: k = 3, n = 7
Output:
[[1,2,4]]
Example 2:
Input: k = 3, n = 9
Output:
[[1,2,6], [1,3,5], [2,3,4]]
https://leetcode.com/problems/combination-sum-iii/
我做到现在AC最快的题目，真的不到1分钟，还是上两题的变通：
http://www.cnblogs.com/Liok3187/p/4526863.html
http://www.cnblogs.com/Liok3187/p/4532064.html
把第二题的代码copy过来，删掉visited，candidates换成一到9，最后加上个数的限制，就好了。
真会玩啊，一个类型翻来覆去，很欢迎Combination Sum IV
1 /** 2 * @param {number} k 3 * @param {number} n 4 * @return {number[][]} 5 */ 6 var combinationSum3 = function(k, n) { 7 var res = []; 8 var candidates = [1,2,3,4,5,6,7,8,9]; 9 candidates.sort(sorting); 10 bfs(0, -1, []); 11 return res; 12 13 function bfs(sum, index, tmp){ 14 var newTmp = null; 15 if(sum === n && tmp.length === k){ 16 newTmp = tmp.concat(); 17 res.push(newTmp); 18 return; 19 }else if(tmp.length > k || sum > n || index + 1 >= candidates.length){ 20 return; //pruning 21 } 22 23 for(var i = index + 1; i < candidates.length; i++){ 24 newTmp = tmp.concat(); 25 newTmp.push(candidates[i]); 26 bfs(sum + candidates[i], i, newTmp); 27 } 28 } 29 function sorting(a, b){ 30 if(a > b){ 31 return 1; 32 }else if(a < b){ 33 return -1; 34 }else{ 35 return 0; 36 } 37 } 38 };
[LeetCode][JavaScript]Combination Sum III
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原文地址：http://www.cnblogs.com/Liok3187/p/4532091.html
