155. Min Stack
Last updated
Last updated
/**
* Time complexity :
* Space complexity :
*/
class MinStack {
private LinkedList<Integer> list;
private int min = Integer.MAX_VALUE;
/** initialize your data structure here. */
public MinStack() {
list = new LinkedList();
}
public void push(int x) {
if(x < min) min = x;
list.add(x);
}
public void pop() {
if(list.isEmpty()) return;
if(list.removeLast() == min) {
min = Integer.MAX_VALUE;
for(int n: list) {
if(n < min) min = n;
}
}
}
public int top() {
if(list.isEmpty()) return -1;
return list.peekLast();
}
public int getMin() {
return min;
}
}
/**
* Your MinStack object will be instantiated and called as such:
* MinStack obj = new MinStack();
* obj.push(x);
* obj.pop();
* int param_3 = obj.top();
* int param_4 = obj.getMin();
*//**
* Time complexity : O(1) for all operations.
* Space complexity : O(N)
*/
class MinStack {
private Stack<Integer> stack = new Stack<>();
private Stack<Integer> minStack = new Stack<>();
public MinStack() { }
public void push(int x) {
stack.push(x);
if (minStack.isEmpty() || x <= minStack.peek()) {
minStack.push(x);
}
}
public void pop() {
if (stack.peek().equals(minStack.peek())) {
minStack.pop();
}
stack.pop();
}
public int top() {
return stack.peek();
}
public int getMin() {
return minStack.peek();
}
}
/**
* Your MinStack object will be instantiated and called as such:
* MinStack obj = new MinStack();
* obj.push(x);
* obj.pop();
* int param_3 = obj.top();
* int param_4 = obj.getMin();
*//**
* Time complexity : O(1) for all operations.
* Space complexity : O(N)
*/
class MinStack {
private Stack<Integer> stack = new Stack<>();
private Stack<int[]> minStack = new Stack<>();
/** initialize your data structure here. */
public MinStack() {
}
public void push(int x) {
stack.push(x);
if (minStack.isEmpty() || x < minStack.peek()[0]) {
minStack.push(new int[]{x, 1});
} else if (x == minStack.peek()[0]) {
minStack.peek()[1]++;
}
}
public void pop() {
if (stack.peek().equals(minStack.peek()[0])) {
minStack.peek()[1]--;
}
if (minStack.peek()[1] == 0) {
minStack.pop();
}
stack.pop();
}
public int top() {
return stack.peek();
}
public int getMin() {
return minStack.peek()[0];
}
}
/**
* Your MinStack object will be instantiated and called as such:
* MinStack obj = new MinStack();
* obj.push(x);
* obj.pop();
* int param_3 = obj.top();
* int param_4 = obj.getMin();
*/