_{[0225 - Implement Stack Using Queues](https://leetcode.com/problems/implement-stack-using-queues/)} | _{<div align='center'>[✔️](c%2F0225-implement-stack-using-queues.c)</div>} | _{<div align='center'>[✔️](cpp%2F0225-implement-stack-using-queues.cpp)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](go%2F0225-implement-stack-using-queues.go)</div>} | _{<div align='center'>[✔️](java%2F0225-implement-stack-using-queues.java)</div>} | _{<div align='center'>[✔️](javascript%2F0225-implement-stack-using-queues.js)</div>} | _{<div align='center'>[✔️](kotlin%2F0225-implement-stack-using-queues.kt)</div>} | _{<div align='center'>[✔️](python%2F0225-implement-stack-using-queues.py)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](rust%2F0225-implement-stack-using-queues.rs)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](typescript%2F0225-implement-stack-using-queues.ts)</div>}

_{[0155 - Min Stack](https://leetcode.com/problems/min-stack/)} | _{<div align='center'>[✔️](c%2F0155-min-stack.c)</div>} | _{<div align='center'>[✔️](cpp%2F0155-min-stack.cpp)</div>} | _{<div align='center'>[✔️](csharp%2F0155-min-stack.cs)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](go%2F0155-min-stack.go)</div>} | _{<div align='center'>[✔️](java%2F0155-min-stack.java)</div>} | _{<div align='center'>[✔️](javascript%2F0155-min-stack.js)</div>} | _{<div align='center'>[✔️](kotlin%2F0155-min-stack.kt)</div>} | _{<div align='center'>[✔️](python%2F0155-min-stack.py)</div>} | _{<div align='center'>[✔️](ruby%2F0155-min-stack.rb)</div>} | _{<div align='center'>[✔️](rust%2F0155-min-stack.rs)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](swift%2F0155-min-stack.swift)</div>} | _{<div align='center'>[✔️](typescript%2F0155-min-stack.ts)</div>}

_{[0150 - Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/)} | _{<div align='center'>[✔️](c%2F0150-evaluate-reverse-polish-notation.c)</div>} | _{<div align='center'>[✔️](cpp%2F0150-evaluate-reverse-polish-notation.cpp)</div>} | _{<div align='center'>[✔️](csharp%2F0150-evaluate-reverse-polish-notation.cs)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](go%2F0150-evaluate-reverse-polish-notation.go)</div>} | _{<div align='center'>[✔️](java%2F0150-evaluate-reverse-polish-notation.java)</div>} | _{<div align='center'>[✔️](javascript%2F0150-evaluate-reverse-polish-notation.js)</div>} | _{<div align='center'>[✔️](kotlin%2F0150-evaluate-reverse-polish-notation.kt)</div>} | _{<div align='center'>[✔️](python%2F0150-evaluate-reverse-polish-notation.py)</div>} | _{<div align='center'>[✔️](ruby%2F0150-evaluate-reverse-polish-notation.rb)</div>} | _{<div align='center'>[✔️](rust%2F0150-evaluate-reverse-polish-notation.rs)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](swift%2F0150-evaluate-reverse-polish-notation.swift)</div>} | _{<div align='center'>[✔️](typescript%2F0150-evaluate-reverse-polish-notation.ts)</div>}

_{[2390 - Removing Stars From a String](https://leetcode.com/problems/removing-stars-from-a-string/)} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](java%2F2390-removing-stars-from-a-string.java)</div>} | _{<divalign='center'>[✔️](javascript%2F2390-removing-stars-from-a-string.js)</div>} | _{<divalign='center'>[✔️](kotlin%2F2390-removing-stars-from-a-string.kt)</div>} | _{<divalign='center'>[✔️](python%2F2390-removing-stars-from-a-string.py)</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>}

_{[2390 - Removing Stars From a String](https://leetcode.com/problems/removing-stars-from-a-string/)} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](cpp%2F2390-removing-stars-from-a-string.cpp)</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](java%2F2390-removing-stars-from-a-string.java)</div>} | _{<divalign='center'>[✔️](javascript%2F2390-removing-stars-from-a-string.js)</div>} | _{<divalign='center'>[✔️](kotlin%2F2390-removing-stars-from-a-string.kt)</div>} | _{<divalign='center'>[✔️](python%2F2390-removing-stars-from-a-string.py)</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>}

_{[0946 - Validate Stack Sequences](https://leetcode.com/problems/validate-stack-sequences/)} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](java%2F0946-validate-stack-sequences.java)</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](kotlin%2F0946-validate-stack-sequences.kt)</div>} | _{<divalign='center'>[✔️](python%2F0946-validate-stack-sequences.py)</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>}

_{[0022 - Generate Parentheses](https://leetcode.com/problems/generate-parentheses/)} | _{<div align='center'>[✔️](c%2F0022-generate-parentheses.c)</div>} | _{<div align='center'>[✔️](cpp%2F0022-generate-parentheses.cpp)</div>} | _{<div align='center'>[✔️](csharp%2F0022-generate-parentheses.cs)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](go%2F0022-generate-parentheses.go)</div>} | _{<div align='center'>[✔️](java%2F0022-generate-parentheses.java)</div>} | _{<div align='center'>[✔️](javascript%2F0022-generate-parentheses.js)</div>} | _{<div align='center'>[✔️](kotlin%2F0022-generate-parentheses.kt)</div>} | _{<div align='center'>[✔️](python%2F0022-generate-parentheses.py)</div>} | _{<div align='center'>[✔️](ruby%2F0022-generate-parentheses.rb)</div>} | _{<div align='center'>[✔️](rust%2F0022-generate-parentheses.rs)</div>} | _{<div align='center'>❌</div>} | _{<div align='center'>[✔️](swift%2F0022-generate-parentheses.swift)</div>} | _{<div align='center'>[✔️](typescript%2F0022-generate-parentheses.ts)</div>}

_{[0735 - Asteroid Collision](https://leetcode.com/problems/asteroid-collision/)} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](cpp%2F0735-asteroid-collision.cpp)</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](java%2F0735-asteroid-collision.java)</div>} | _{<divalign='center'>[✔️](javascript%2F0735-asteroid-collision.js)</div>} | _{<divalign='center'>[✔️](kotlin%2F0735-asteroid-collision.kt)</div>} | _{<divalign='center'>[✔️](python%2F0735-asteroid-collision.py)</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](rust%2F0735-asteroid-collision.rs)</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>❌</div>} | _{<divalign='center'>[✔️](typescript%2F0735-asteroid-collision.ts)</div>}

classSolution {

stringremoveStars(string s) {

stack<char> stk;

for(int i=0;i<s.size();i++){

if(s[i]=='*'){

stk.pop();

}else stk.push(s[i]);

}

string res ="";

while(!stk.empty()){

res += stk.top();

stk.pop();

}

reverse(res.begin(), res.end());

return res;

}

};

classSolution {

publicbooleanleafSimilar(TreeNoderoot1,TreeNoderoot2) {

ArrayList<Integer>ls1 =newArrayList<>();

ArrayList<Integer>ls2 =newArrayList<>();

tree(root1,ls1);

tree(root2,ls2);

returnls1.equals(ls2);

}

privatevoidtree(TreeNoderoot,List<Integer>ls){

if(root ==null)

return;

if(root.left ==null &&root.right ==null)

ls.add(root.val);

tree(root.left,ls);

tree(root.right,ls);

}

}

classSolution {

publicintamountOfTime(TreeNoderoot,intstart) {

Map<Integer,List<Integer>>g =treeTograph(root);

inttime =0;

Queue<Integer>q =newLinkedList<>();

Set<Integer>visited =newHashSet<>();

q.add(start);

visited.add(start);

while(!q.isEmpty()){

intsize =q.size();

for (inti =0;i <size;i++) {

intcurr =q.poll();

for (intneighbour :g.get(curr)) {

if (!visited.contains(neighbour)) {

q.add(neighbour);

visited.add(neighbour);

}

}

}

time++;

}

returntime-1;

}

publicHashMap<Integer,List<Integer>>treeTograph(TreeNoderoot) {

HashMap<Integer,List<Integer>>graph =newHashMap<>();

buildGraph(root,graph);

returngraph;

}

privatevoidbuildGraph(TreeNodenode,HashMap<Integer,List<Integer>>graph) {

if (node ==null) {

return;

}

graph.putIfAbsent(node.val,newArrayList<>());

if (node.left !=null) {

graph.get(node.val).add(node.left.val);

graph.putIfAbsent(node.left.val,newArrayList<>());

graph.get(node.left.val).add(node.val);

buildGraph(node.left,graph);

}

if (node.right !=null) {

graph.get(node.val).add(node.right.val);

graph.putIfAbsent(node.right.val,newArrayList<>());

graph.get(node.right.val).add(node.val);

buildGraph(node.right,graph);

}

}

}

classSolution {

funleafSimilar(root1:TreeNode?,root2:TreeNode?):Boolean {

fundfs(root:TreeNode?,res:MutableList<Int>) {

root?:return

if (root.left==null&& root.right==null)

res.add(root.`val`)

dfs(root.left, res)

dfs(root.right, res)

}

val res1:MutableList<Int>=mutableListOf()

val res2:MutableList<Int>=mutableListOf()

dfs(root1, res1)

dfs(root2, res2)

return res1== res2

}

}