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); } } }