Path Sum II

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           /   /           /  4         /  \    /         7 2 5   1

Return

[   [5,4,11,2],   [5,8,4,5]]

This problem is not own a out, looked at the discuss area inside, but the writing is really beautiful

1  Packagecom.gxf.test;2 3 Importjava.util.ArrayList;4 Importjava.util.List;5 ImportJava.util.Stack;6 7 8 9    classTreeNode {Ten       intVal; One TreeNode left; A TreeNode right; -TreeNode (intX) {val =x;} -   } the  -     Public classSolution { -          PublicList<list<integer>> pathsum (TreeNode root,intsum) { -list<list<integer>> result =NewArraylist<list<integer>>(); +             if(NULL==root) -                 returnresult; +             if(NULL= = Root.left &&NULL= = Root.right) {//leaf knot Point A                 if(Root.val = =sum) { atlist<integer> element =NewArraylist<integer>(); - element.add (sum); - Result.add (element); -                 } -}Else{ -result = Pathsum (Root.left, sum-root.val);//get all the paths to the left subtree inlist<list<integer>> result_right = Pathsum (Root.right, sum-root.val);//get all paths to right subtree - Result.addall (result_right); to                  +                  for(list<integer>Element:result) { -Element.add (0, Root.val);//Add the root node to the first location the                 } *             } $             Panax Notoginseng             returnresult; -         } the}

Another type of Dfs

1  Packagecom.gxf.test;2 3 Importjava.util.ArrayList;4 Importjava.util.List;5 ImportJava.util.Stack;6 7 8 9    classTreeNode {Ten       intVal; One TreeNode left; A TreeNode right; -TreeNode (intX) {val =x;} -   } the  -     Public classSolution { -          PublicList<list<integer>> pathsum (TreeNode root,intsum) { -list<list<integer>> result =NewArraylist<list<integer>>(); +List<integer> currentelement =NewArraylist<integer>(); -              + GetPath (root, Sum, result, currentelement); A              at             returnresult; -         } -          -         /** - * Recursive get result -          * @paramRoot in          * @paramsum -          * @paramreuslt to          * @paramCurrentresult +          */ -          Public voidGetPath (TreeNode root,intSum, list<list<integer>> result, list<integer>Currentresult) { the             if(NULL==root) *                 return; $Currentresult.add (Root.val);//Add to CurrentresultPanax Notoginseng             if(NULL= = Root.left &&NULL= = Root.right) {//leaf knot Point -                 if(Sum = =root.val) { theResult.add (NewArraylist<integer> (Currentresult));//Add to result +                 } ACurrentresult.remove (Currentresult.size ()-1);//Remove the leaf nodes. the                 return ; +             } -             Else{//non-leaf knot point $GetPath (Root.left, Sum-root.val, result, Currentresult);//traversing the left sub-tree $GetPath (Root.right, Sum-root.val, result, Currentresult);//traversing the right sub-tree -                  -             } the              -Currentresult.remove (Currentresult.size ()-1);//when the recursion is returned, none of this will delete the leaf node.Wuyi         } the}

Path Sum II