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leetcode-day6

admin 11月 11, 2020 0

进入medium 的tree了，这个有bug，明天继续

Path Sum II

https://leetcode.com/problems/path-sum-ii/
要记得每次递归过后，要把上一次的pop()出来。



 * @param {TreeNode} root
 * @param {number} sum
 * @return {number[][]}
 */
var pathSum = function(root, sum) {
    var res = [];
    if(root === null){
        return res;
    }
    var list = [];
    list.push(root.val);
    helper(root, sum- root.val, list, res);
    return res;
    
};

var helper = function(root, sum, list, res){
    if(root === null){
        return ;
    }
    if(root.left === null && root.right === null && sum === 0){
        res.push(list.slice());
        return;
    }
    if(root.left !== null){
        list.push(root.left.val);
        helper(root.left, sum - root.left.val, list, res);
        list.pop();
    }
    if(root.right !== null){
        list.push(root.right.val);
        helper(root.right, sum - root.right.val, list, res);
        list.pop();
    }
}