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113. Path Sum II

 

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]]

 

 

 

public IList<IList<int>> PathSum(TreeNode root, int sum) {        IList<IList<int>> res = new List<IList<int>>();        BackTracking(root,sum,new List<int>(),res);        return res;    }        public void BackTracking(TreeNode root, int sum, IList<int> cur,IList<IList<int>> res )    {        if(root != null)        {            if(root.left == null && root.right == null)//leaf check            {                if(sum == root.val)                {                    cur.Add(root.val);                    res.Add(new List<int>(cur));                }            }            else            {                cur.Add(root.val);                BackTracking(root.left,sum - root.val,new List<int>(cur),res);                BackTracking(root.right,sum - root.val,new List<int>(cur),res);            }        }    }

 

113. Path Sum II