Combination Sum III

描述

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]]

分析

这是一个多阶段问题，目标是求所有解，显然用深搜+剪枝，即回溯法。

代码

相关题目

原文: https://soulmachine.gitbooks.io/algorithm-essentials/content/cpp/dfs/combination-sum-iii.html