Java编程 数3退1



数三退一：500个小孩手拉手围成一圈，从第一个小孩开始数数，按照1、2、3、1、2、3循环不断的数，数到3的小孩退出圈，其他小孩接着数，直到剩下一个小孩，问这个小孩的排在什么位置？

<strong>public class Count3Quit1 {public static void main(String[] args) {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);}}class Kid {int id;Kid left;Kid right;}class KidCircle {int count = 0;Kid first, last;KidCircle(int n) {for (int i = 0; i < n; i++) {add();}}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.right = first;k.left = last;first.left = k;last = k;}count++;}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--;}}</strong>