9.17 最小栈 简单

 1 class MinStack {
 2 
 3     /** initialize your data structure here. */
 4     private int stackSize = 1000;
 5     private int top = 0;
 6     private int base = 0;
 7     private int[] stack;
 8     public MinStack() {
 9         stack = new int[stackSize];
10     }
11     
12     public void push(int x) {
13         if(top < stackSize){
14             stack[top++] = x;
15         }
16     }
17     
18     public void pop() {
19         top--;
20     }
21     
22     public int top() {
23         if(top != 0){
24             return stack[top - 1];  
25         }
26         throw new RuntimeException();
27     }
28     public int getMin(){
29         int save = Integer.MAX_VALUE;
30         for(int i = 0; i < top; i++){
31             if(stack[i] < save)
32                 save = stack[i];
33         }
34         return save;
35     }
36 }
37 
38 /**
39  * Your MinStack object will be instantiated and called as such:
40  * MinStack obj = new MinStack();
41  * obj.push(x);
42  * obj.pop();
43  * int param_3 = obj.top();
44  * int param_4 = obj.getMin();
45  */