Combination Sum II LeetCode

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

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

Note: The solution set must not contain duplicate combinations.

 Example 1:

Input: candidates = [10,1,2,7,6,1,5], target = 8
Output: 
[
[1,1,6],
[1,2,5],
[1,7],
[2,6]
]

Example 2:

Input: candidates = [2,5,2,1,2], target = 5
Output: 
[
[1,2,2],
[5]
]

 NOTE:

• 1 <= candidates.length <= 100
• 1 <= candidates[i] <= 50
• 1 <= target <= 30

This problem is popular in LeetCode  A collection of hundreds of interview questions and solutions are available in our blog at Interview Question Solutions

Solution

Source: Java

	/**
	Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sums to target.
	Each number in candidates may only be used once in the combination.
	Note:
	All numbers (including target) will be positive integers.
	The solution set must not contain duplicate combinations.
	Example 1:
	Input: candidates = [10,1,2,7,6,1,5], target = 8,
	A solution set is:
	[
	[1, 7],
	[1, 2, 5],
	[2, 6],
	[1, 1, 6]
	]
	Example 2:
	Input: candidates = [2,5,2,1,2], target = 5,
	A solution set is:
	[
	[1,2,2],
	[5]
	]
	*/
	import java.util.Arrays;
	import java.util.List;
	import java.util.ArrayList;
	public class CombinationSumII{
	public static List<List<Integer>> combSum(int[] nums, int target){
	//base case
	List<List<Integer>> lists = new ArrayList<List<Integer>>();
	Arrays.sort(nums);
	combSumRecursive(lists, new ArrayList<Integer>(), nums, 0, target);
	return lists;
	}
	public static void combSumRecursive(List<List<Integer>> lists, List<Integer> tempList, int[] nums, int start, int rem){
	if(rem<0){
	return;
	}else if(rem==0){//we found a sum
	lists.add(new ArrayList<>(tempList));
	}else{
	for(int i=start;i<nums.length; i++){
	//handle duplicates
	if(i>start && nums[i]==nums[i-1]) continue;
	tempList.add(nums[i]);
	combSumRecursive(lists, tempList, nums, i+1, rem-nums[i]);
	tempList.remove(tempList.size()-1);
	}
	}
	}
	public static void main(String args[]){
	int nums[] = new int[]{10,1,2,7,6,1,5};
	int target = 8;
	//nums = new int[]{2,5,2,1,2};
	//target = 5;
	List<List<Integer>> permsList = combSum(nums, target);
	for(List<Integer> intlist: permsList){
	Integer [] intarr = new Integer[intlist.size()];
	System.out.println(Arrays.toString(intlist.toArray(intarr)));
	}
	}
	}

view raw CombinationSumII.java hosted with ❤ by GitHub