algorithm/Week_02/id_113/leetcode_236_113.java at master · feixiangcode/algorithm · GitHub

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/**

* Definition for a binary tree node.

* public class TreeNode {

* int val;

* TreeNode left;

* TreeNode right;

* TreeNode(int x) { val = x; }

* }

class Solution {

public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {

ArrayList<TreeNode> routes1 = new ArrayList();

ArrayList<TreeNode> routes2 = new ArrayList();

FindRoute(root, p.val, routes1);

FindRoute(root, q.val, routes2);

return Lca(routes1, routes2);

}

public boolean FindRoute(TreeNode root, Integer p, List<TreeNode> routes) {

if(root == null) return false;

routes.add(root);

if(root.val == p) return true;

if(FindRoute(root.left, p, routes)) return true;

if(FindRoute(root.right, p, routes)) return true;

routes.remove(root);

return false;

}

public TreeNode Lca(ArrayList<TreeNode> nodes1, ArrayList<TreeNode> nodes2) {

int c = nodes1.size() > nodes2.size() ? nodes2.size() : nodes1.size();

TreeNode last = null;

for(int i=0;i<c;i++) {

TreeNode a = nodes1.get(i);

TreeNode b = nodes2.get(i);

if(a == b) {

last = a;

} else {

break;

}

return last;

}

algorithm/Week_02/id_113/leetcode_236_113.java at master · feixiangcode/algorithm · GitHub

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