Package g0001_0100.s0039_combination_sum

Class Solution

java.lang.Object

g0001_0100.s0039_combination_sum.Solution

public class Solution
extends Object

39 - Combination Sum.

Medium

Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum to target. You may return the combinations in any order.

The same number may be chosen from candidates an unlimited number of times. Two combinations are unique if the frequency of at least one of the chosen numbers is different.

It is guaranteed that the number of unique combinations that sum up to target is less than 150 combinations for the given input.

Example 1:

Input: candidates = [2,3,6,7], target = 7

Output: [[2,2,3],[7]]

Explanation:

 2 and 3 are candidates, and 2 + 2 + 3 = 7. Note that 2 can be used multiple times.
 7 is a candidate, and 7 = 7.
 These are the only two combinations. 

Example 2:

Input: candidates = [2,3,5], target = 8

Output: [[2,2,2,2],[2,3,3],[3,5]]

Example 3:

Input: candidates = [2], target = 1

Output: []

Example 4:

Input: candidates = [1], target = 1

Output: 1

Example 5:

Input: candidates = [1], target = 2

Output: 1,1

Constraints:

• 1 <= candidates.length <= 30
• 1 <= candidates[i] <= 200
• All elements of candidates are distinct.
• 1 <= target <= 500

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
List<List<Integer>>	combinationSum(int[] coins, int amount)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

combinationSum

public List<List<Integer>> combinationSum(int[] coins,
                                          int amount)