packagemedium;

importjava.util.ArrayList;

importjava.util.List;

importclasses.TreeNode;

publicclassFindLeavesofBinaryTree {

List<List<Integer>>result =newArrayList<List<Integer>>();

publicList<List<Integer>>findLeaves(TreeNoderoot) {

dfs(root);

returnresult;

}

intdfs(TreeNoderoot){

if(root ==null)return0;

intlevel =Math.max(dfs(root.left),dfs(root.right))+1;

if(result.size() <level){

result.add(newArrayList<Integer>());

}

result.get(level-1).add(root.val);

returnlevel;

}

}

|379|[Design Phone Directory](https://leetcode.com/problems/design-phone-directory/)|[Solution](../../blob/master/MEDIUM/src/medium/DesignPhoneDirectory.java)| O(1)|O(n)| Medium|

|374|[Guess Number Higher or Lower](https://leetcode.com/problems/guess-number-higher-or-lower/)|[Solution](../../blob/master/EASY/src/easy/GuessNumberHigherorLower.java)| O(logn)|O(1) | Easy| Binary Search

|370|[Range Addition](https://leetcode.com/problems/range-addition/)|[Solution](../../blob/master/MEDIUM/src/medium/RangeAddition.java)| O(n+k)|O(1)| Medium|

|366|[Find Leaves of Binary Tree](https://leetcode.com/problems/find-leaves-of-binary-tree/)|[Solution](../../blob/master/MEDIUM/src/medium/FindLeavesofBinaryTree.java)| O(n)|O(h) | Medium| DFS

|359|[Logger Rate Limiter](https://leetcode.com/problems/logger-rate-limiter/)|[Solution](../../blob/master/EASY/src/easy/LoggerRateLimiter.java)| amortized O(1)|O(k) | Easy| HashMap

|350|[Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/)|[Solution](../../blob/master/EASY/src/easy/IntersectionOfTwoArraysII.java)| O(m+n)|O((m+n)) could be optimized | Easy| HashMap, Binary Search

|349|[Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays/)|[Solution](../../blob/master/EASY/src/easy/IntersectionOfTwoArrays.java)| O(m+n)|O(min(m,n)) | Easy| Two Pointers, Binary Search