package class03;

public class Code04_RingArray {

public static class MyQueue {

private int[] arr;

private int pushi;// end

private int polli;// begin

private int size;

private final int limit;

public MyQueue(int limit) {

arr = new int[limit];

pushi = 0;

polli = 0;

size = 0;

this.limit = limit;

}

public void push(int value) {

if (size == limit) {

throw new RuntimeException("队列满了，不能再加了");

}

size++;

arr[pushi] = value;

pushi = nextIndex(pushi);

}

public int pop() {

if (size == 0) {

throw new RuntimeException("队列空了，不能再拿了");

}

size--;

int ans = arr[polli];

polli = nextIndex(polli);

return ans;

}

public boolean isEmpty() {

return size == 0;

}

// 如果现在的下标是i，返回下一个位置

private int nextIndex(int i) {

return i < limit - 1 ? i + 1 : 0;

}

}

}