[Vssue]0040.组合总和II.md

private void backtracking(int[] nums, int target, int sum, int start) {
    if (sum == target) {
        paths.add(new ArrayList<>(path));
        return;
    }
    for (int i = start; i < nums.length && sum + nums[i] <= target; i++) {
        if (i > start && nums[i] == nums[i - 1]) continue; // 去重
        sum += nums[i];
        path.add(nums[i]);
        backtracking(nums, target, sum, i + 1);
        sum -= nums[i];
        path.remove(path.size() - 1);
    }
}

// 深度1: backtracking([1,1,2,5,6,7,10], 8, 0, 0), path = []
i = 0：path = [1]，递归 backtracking([1,1,2,5,6,7,10], 8, 0, 1)，回溯，path = []
i = 1：满足 1 == 1, 继续遍历（剪枝） ...
i = 6：path = [10]，递归 backtracking([1,1,2,5,6,7,10], 8, 0, 7)，回溯，path = []
// 深度2: 例: backtracking([1,1,2,5,6,7,10], 8, 0, 1), path = [1]
i = 1：path = [1,1]，递归 backtracking([1,1,2,5,6,7,10], 8, 0, 2)，回溯，path = [1] ...
i = 5：path = [1,7]，递归 backtracking([1,1,2,5,6,7,10], 8, 0, 8)，回溯，path = [1]
i = 6：不满足 1 + 10 <= 8, 停止遍历（剪枝）
// 深度3: 例: backtracking([1,1,2,5,6,7,10], 8, 0, 2), path = [1,1]
i = 2：path = [1,1,2]，递归 backtracking([1,1,2,5,6,7,10], 8, 0, 3)，回溯，path = [1,1] ...
i = 5：不满足 2 + 7 <= 8, 停止遍历（剪枝）
// 深度n: 以此类推

youngyangyang04 / leetcode-master-comment

[Vssue]0040.组合总和II.md #90