Lintcode 153. Combination Sum II

题目链接：https://www.lintcode.com/problem/combination-sum-ii/description

/**
* @param num: Given the candidate numbers
* @param target: Given the target number
* @return: All the combinations that sum to target
*/
func combinationSum2(num []int, target int) [][]int {
	// write your code here
	var results [][]int = [][]int{};
	if (num == nil || len(num) == 0) {
		return results;
	}
	sort.Ints(num);
	var combination []int;
	helper(num, 0, combination, target, &results);
	return results;
}

func helper(num []int, startIndex int, combination []int, target int, results *[][]int) {
	if (target == 0) {
		tmp := []int{};
		tmp = append(tmp, combination...);
		*results = append(*results, tmp);
		//fmt.Println(results);
		return;
	}
	var i int;
	for i = startIndex; i < len(num); i++ {
		//这一步没必要，是跑不到的，每一次重复元素又变成了新的头元素
		if (i != startIndex && num[i] == num[i-1]) {
			continue;
		}
		if (target < num[i]) {
			break;
		}
		var addCom = append(combination, num[i]);
		helper(num, i+1, addCom, target-num[i], results);
	}
}

func main() {
	var num1 []int = []int{7, 1, 2, 5, 1, 6, 10};
	var target1 int = 8;
	var combination1 [][]int = combinationSum2(num1, target1);
	fmt.Println(combination1);

	var num2 []int = []int{};
	var target2 int = 1;
	var combination2 [][]int = combinationSum2(num2, target2);
	fmt.Println(combination2);
}