-
Notifications
You must be signed in to change notification settings - Fork 1
Expand file tree
/
Copy pathMinStack.java
More file actions
71 lines (60 loc) · 1.96 KB
/
Copy pathMinStack.java
File metadata and controls
71 lines (60 loc) · 1.96 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
// Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.
// push(x) -- Push element x onto stack.
// pop() -- Removes the element on top of the stack.
// top() -- Get the top element.
// getMin() -- Retrieve the minimum element in the stack
// See: https://leetcode.com/problems/min-stack/
// See: https://leetcode.com/explore/featured/card/30-day-leetcoding-challenge/529/week-2/3292/
package leetcode.stack;
import java.util.Stack;
class MinStack {
Stack<Integer> stack = new Stack<>();
Stack<Integer> minStack = new Stack<>();
public MinStack() {
}
public void push(int x) {
if (minStack.isEmpty() || x <= minStack.peek())
minStack.push(x);
stack.push(x);
}
public void pop() {
if (stack.peek() <= minStack.peek())
minStack.pop();
stack.pop();
}
public int top() {
return stack.peek();
}
public int getMin() {
return minStack.peek();
}
public static void main(String[] args) {
MinStack minStack = new MinStack();
minStack.push(512);
minStack.push(-1024);
minStack.push(-1024);
minStack.push(512);
minStack.pop();
System.out.println(minStack.getMin());
minStack.pop();
System.out.println(minStack.getMin());
minStack.pop();
System.out.println(minStack.getMin());
System.out.println();
minStack = new MinStack();
minStack.push(-2);
minStack.push(0);
minStack.push(-3);
System.out.println(minStack.getMin());
minStack.pop();
System.out.println(minStack.top());
System.out.println(minStack.getMin());
minStack.push(-5);
minStack.push(4);
System.out.println(minStack.getMin());
minStack.pop();
System.out.println(minStack.getMin());
minStack.pop();
System.out.println(minStack.getMin());
}
}