package codingInterview;

import java.util.Arrays;

public class MinStack {

private int MAX_LEN = 100;

private int[] arr;

private int capacity = -1;

public MinStack() {

this.arr = new int[MAX_LEN];

capacity = 0;

}

private void push(int elem) {

if (capacity >= MAX_LEN) {

System.out.println("out of capacity, extend the capacity");

arr = Arrays.copyOf(arr, MAX_LEN * 2);

}

arr[capacity] = elem;

capacity++;

}

private int pop() {

if (capacity <= 0) {

System.out.println("out of capacity");

return Integer.MIN_VALUE;

}

if (capacity == arr.length / 2 && arr.length > MAX_LEN) {

System.out.println("narrow the space of stack");

Arrays.copyOf(arr, arr.length / 2);

}

capacity--;

return arr[capacity];

}

private int top() {

if (capacity <= 0) {

System.out.println("out of range");

return Integer.MIN_VALUE;

}

return arr[capacity - 1];

}

private int getMin() {

if (capacity <= 0 || capacity >= arr.length) {

System.out.println("out of range");

return Integer.MIN_VALUE;

}

int min = Integer.MAX_VALUE;

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

if (arr[i] < min) {

min = arr[i];

}

}

return min;

}

public static void main(String[] args) {

// TODO Auto-generated method stub

MinStack stack = new MinStack();

stack.push(5);

stack.push(3);

stack.push(10);

stack.push(0);

for (int i = 0; i < 100; i++) {

stack.push(i);

}

System.out.println(stack.top());

System.out.println(stack.pop());

System.out.println(stack.capacity);

System.out.println(stack.getMin());

}

}