packageeasy;

importjava.util.*;

publicclassMinStack {

privateStack<Integer>stack;

privateintmin;

publicMinStack() {

stack =newStack();

min =Integer.MAX_VALUE;

}

publicvoidpush(intx) {

if(x <=min){

stack.push(min);

min =x;

}

stack.push(x);

}

publicvoidpop() {

if(min ==stack.peek()){

stack.pop();

min =stack.pop();

}else {

stack.pop();

}

if(stack.isEmpty())min =Integer.MAX_VALUE;

}

publicinttop() {

returnstack.peek();

}

publicintgetMin() {

returnmin;

}

}

|173|[Binary Search Tree Iterator](https://leetcode.com/problems/binary-search-tree-iterator/)|[Queue](../../blob/master/MEDIUM/src/medium/BSTIterator_using_q.java)[Stack](../../blob/master/MEDIUM/src/medium/BSTIterator_using_stack.java)| O(1)|O(h)| Medium|

|172|[Factorial Trailing Zeroes](https://leetcode.com/problems/factorial-trailing-zeroes/)|[Solution](../../blob/master/EASY/src/easy/FactorialTrailingZeroes.java)| O(logn)|O(1)| Easy

|162|[Find Peak Element](https://leetcode.com/problems/find-peak-element/)|[Solution](../../blob/master/MEDIUM/src/medium/FindPeakElement.java)| O(1)|O(logn)/O(n)| Binary Search|

|155|[Min Stack](https://leetcode.com/problems/min-stack/)|[Solution](../../blob/master/EASY/src/easy/MinStack.java)| O(1)|O(n) | Easy| Stack

|140|[Word Break II](https://leetcode.com/problems/word-break-ii/)|[Solution](../../blob/master/HARD/src/hard/WordBreakII.java)| ? |O(n^2) | Hard| Backtracking/DFS

|139|[Word Break](https://leetcode.com/problems/word-break/)|[Solution](../../blob/master/MEDIUM/src/medium/WordBreak.java)| O(n^2)|O(n) | Medium| DP

|133|[Clone Graph](https://leetcode.com/problems/clone-graph/)|[Solution](../../blob/master/MEDIUM/src/medium/CloneGraph.java)| O(n)|O(n) | Medium| HashMap, BFS