## 代码
~~~java
class TripleInOne {

int[] arr;
    int stackSize;

public TripleInOne(int stackSize) {
        this.stackSize=stackSize;
        arr=new int[stackSize*4];
    }
    
    public void push(int stackNum, int value) {
        if(stackSize==0 || arr[stackNum]==stackSize) {
            return;
        }
        arr[arr[stackNum]+stackSize*(stackNum+1)]=value;
        arr[stackNum]++;
    }
    
    public int pop(int stackNum) {
        if(stackSize==0 || arr[stackNum]<1)  {
            return -1;
        }
        return (arr[stackNum]<1)?-1:arr[arr[stackNum]--+stackSize*(stackNum+1)-1];
    }
    
    public int peek(int stackNum) {
        if(stackSize==0) return -1;
        return (arr[stackNum]<1)?-1:arr[arr[stackNum]+stackSize*(stackNum+1)-1];
    }
    
    public boolean isEmpty(int stackNum) {
        if(stackSize==0) return true;
        return arr[stackNum]==0;
    }
}

/**
 * Your TripleInOne object will be instantiated and called as such:
 * TripleInOne obj = new TripleInOne(stackSize);
 * obj.push(stackNum,value);
 * int param_2 = obj.pop(stackNum);
 * int param_3 = obj.peek(stackNum);
 * boolean param_4 = obj.isEmpty(stackNum);
 */
~~~

面试题 03.01. 三合一

目录