JZ24 二叉树中和为某一值的路径

本文最后更新于：2022年4月9日 中午

image-20211008102237901

Solution

  • 回溯法
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/*
struct TreeNode {
	int val;
	struct TreeNode *left;
	struct TreeNode *right;
	TreeNode(int x) :
			val(x), left(NULL), right(NULL) {
	}
};*/
class Solution {
public:
    vector<vector<int> > FindPath(TreeNode* root,int expectNumber) {
        res.clear();
        vector<int> path;
        if (root == nullptr) return res;
        
        backtrack(root, expectNumber, path);
        return res;
    }
private:
    vector<vector<int>> res;
    
    void backtrack(TreeNode* root, int target, vector<int> path) {
        path.push_back(root->val);
        target -= root->val;
        if (target == 0 && root->left == nullptr && root->right == nullptr) {
            res.push_back(path);
            return;
        }
        if (root == nullptr || target < 0) return;
        
        if (root->left) {
            backtrack(root->left, target, path);
        }
        if (root->right) {
            backtrack(root->right, target, path);
        }
        path.pop_back();
        return;
    }
};