java数组小游戏——数三退一

Count3Quit.java

//数3退1，小游戏算法测试
/*
	若干个人围成一圈，从第一个人开始数，数到第三个人，第三个人退出，
	继续从1开始数，到3退出
*/
public class Count3Quit {
	public static void main(String[] args) {
		
		//500个人拉成一圈，用数组模拟
		boolean[] arr = new boolean[500];
		for(int i=0; i<arr.length; i++) {
			arr[i] = true;
		}
				
		int leftCount = arr.length;//还剩多少个人
		int countNum = 0;//计数器
		int index = 0;//第0个人
		
		while(leftCount > 1) {
			if(arr[index] == true) {
				countNum ++;
				if(countNum == 3) {
					countNum = 0;
					arr[index] = false;
					leftCount --;
				}
			}
			
			index ++;
			
			//如果index等于arr.length,index回0
			if(index == arr.length) {
				index = 0;
			}
		}
		
		//找到剩下为true的数
		for(int i=0; i<arr.length; i++) {
			if(arr[i] == true) {
				System.out.println(i);//i=435，下标为435，为第436个人
			}
		}
	}
}

 

F:\java>javac Count3Quit.java

F:\java>java Count3Quit
435

F:\java>

 

 Count3Quit2.java

/*
	面向对象的写法：
	数三退一，500个小孩围成一圈
*/
public class Count3Quit2 {
	public static void main(String[] args) {
		//面向对象的写法
		KidCircle kc = new KidCircle(500);
		int countNum = 0;
		Kid k = kc.first;
		while(kc.count > 1) {
			countNum ++;
			if(countNum == 3) {
				countNum = 0;
				kc.delete(k);
			}
			k = k.right;
		}
		
		System.out.println(kc.first.id);
	}
}

//小孩类
class Kid {
	int id;
	Kid left;//小孩的左边
	Kid right;//小孩的右边
}

//小孩围成的圈
class KidCircle {
	int count = 0;
	Kid first, last;//开始的小孩和结束的小孩
	
	KidCircle(int n) {
		for(int i=0; i<n; i++) {
			add();
		}
	}
	
	//添加一个小孩
	void add() {
		Kid k = new Kid();
		k.id = count;
		if(count <= 0) {
			first = k;
			last = k;
			k.left = k;
			k.right = k;
		} else {
			last.right = k;
			k.left = last;
			k.right = first;
			first.left = k;
			last = k;
		}
		count ++;
	}
	
	//删除一个小孩
	void delete(Kid k) {
		if(count <= 0) {
			return;
		} else if (count == 1) {
			first = last = null;
		} else {
			k.left.right = k.right;
			k.right.left = k.left;
			
			if(k == first) {
				first = k.right;
			} else if( k == last) {
				last = k.left;
			}
		}
		count --;
	}
}

 

F:\java>javac Count3Quit2.java

F:\java>java Count3Quit2
435

F:\java>