Leetcode 39 Combination Sum & 40 Combination Sum II & 216 Combination Sum III & 377 Combination V - fantasia的博客 - CSDN博客

Leetcode 39 Combination Sum & 40 Combination Sum II & 216 Combination Sum III & 377 Combination V - fantasia的博客 - CSDN博客

39. Combination Sum

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

The same repeated number may be chosen from C unlimited number of times.

Note:

• All numbers (including target) will be positive integers.
• The solution set must not contain duplicate combinations.

For example, given candidate set [2, 3, 6, 7] and target 7, 
A solution set is: 

[    [7],    [2, 2, 3]  ]

思路：

可以重复使用元素。那么每次调用从当前位置开始，如果当前位置元素小于目标元素，加入path，再次从当前位置调用；每个call中都要遍历后面的可能位置一遍。因此排序+剪枝。

Read full article from Leetcode 39 Combination Sum & 40 Combination Sum II & 216 Combination Sum III & 377 Combination V - fantasia的博客 - CSDN博客