剑指 Offer 34. 二叉树中和为某一值的路径

剑指 Offer 34. 二叉树中和为某一值的路径

dfs

class Solution {
public:
    vector<vector<int>>res;
    vector<vector<int>> pathSum(TreeNode* root, int sum) {
        if(!root) return res;
        vector<int>path;
        dfs(root,path,sum);
        return res;
    }
    
    void dfs(TreeNode *root,vector<int> &path,int sum){
        sum-=root->val;
        path.push_back(root->val);
        if(root->left==NULL && root->right==NULL){
            if(sum==0) res.push_back(path);
            path.pop_back();
            return;
        }
        
        if(root->left)dfs(root->left,path,sum);
        if(root->right)dfs(root->right,path,sum);
        path.pop_back();

    }
};