Path Sum II

最新推荐文章于 2024-10-26 02:26:14 发布

IIcyZhao

最新推荐文章于 2024-10-26 02:26:14 发布

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分类专栏： LeetCode记录

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本文介绍了一种算法，用于查找二叉树中所有从根节点到叶子节点的路径，其中路径上节点值的总和等于给定的目标值。通过递归方式遍历二叉树，记录符合条件的路径。

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Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.

For example:
Given the below binary tree and

sum
 = 22

              5
             / \
            4   8
           /   / \
          11  13  4
         /  \    / \
        7    2  5   1

return

[
   [5,4,11,2],
   [5,8,4,5]
]

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<vector<int> > pathSum(TreeNode *root, int sum) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<vector<int> > result;
        vector<int> path;
        GetpathSum(root, sum, path, result);
        return result;
    }
    
private:
    void GetpathSum(TreeNode* root, int sum, vector<int> path, vector<vector<int> >& result) {
       if (root == NULL) {
         return;
       }
       path.push_back(root->val);
       if (root->right == NULL && root->left == NULL) {
           if (root->val == sum) {
               result.push_back(path);
           }
           return;
       } else {
           GetpathSum(root->right, sum - root->val, path, result);
           GetpathSum(root->left, sum - root->val, path, result);
       }
       
    }
};