113. Path Sum II

Medium

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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.

Note: A leaf is a node with no children.

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]
]
class Solution {
private:
    vector<vector<int>> result;
    int score;
public:
    vector<vector<int>> pathSum(TreeNode* root, int sum)
    {
        score = sum;
        if(root == NULL){return result;}
        vector<int> tmp;
        dfs(root,tmp,0);
        return result;
    }
    void dfs(TreeNode *root,vector<int> tmp,int sum)
    {
        tmp.push_back(root->val);
        sum += root->val;
        if(root->left == NULL && root->right == NULL && sum == score){result.push_back(tmp);}
        if(root->left != NULL){dfs(root->left,tmp,sum);}
        if(root->right != NULL){dfs(root->right,tmp,sum);}
    }
};