-
Notifications
You must be signed in to change notification settings - Fork 2
/
CombinationSumII.java
78 lines (69 loc) · 1.94 KB
/
CombinationSumII.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
package Leetcode;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* @author kalpak
*
* 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]
* ]
*
*
* Constraints:
*
* 1 <= candidates.length <= 100
* 1 <= candidates[i] <= 50
* 1 <= target <= 30
*/
public class CombinationSumII {
public static List<List<Integer>> combinationSum2(int[] candidates, int target) {
List<List<Integer>> result = new ArrayList<>();
List<Integer> temp = new ArrayList<>();
Arrays.sort(candidates); // since the candidates are not distinct
backtrack(result, temp, candidates, target, 0);
return result;
}
private static void backtrack(List<List<Integer>> result, List<Integer> temp, int[] candidates, int target, int index) {
if(target < 0)
return;
if(target == 0) {
result.add(new ArrayList<>(temp));
return;
}
for(int i = index; i < candidates.length; i++) {
if(i > index && candidates[i] == candidates[i-1]) // skip duplicates
continue;
temp.add(candidates[i]);
backtrack(result, temp, candidates, target - candidates[i], i+1); // send index i+1 since we cannot reuse
temp.remove(temp.size() - 1);
}
}
public static void main(String[] args) {
int[] nums = new int[]{10,1,2,7,6,1,5};
System.out.println(combinationSum2(nums, 8));
}
}