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package class16;
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// 本题测试链接 : https://leetcode-cn.com/problems/yuan-quan-zhong-zui-hou-sheng-xia-de-shu-zi-lcof/
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public class Code05_JosephusProblem {
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// 提交直接通过
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// 给定的编号是0~n-1的情况下，数到m就杀
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// 返回谁会活？
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public int lastRemaining1(int n, int m) {
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return getLive(n, m) - 1;
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}
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// 课上题目的设定是，给定的编号是1~n的情况下，数到m就杀
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// 返回谁会活？
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public static int getLive(int n, int m) {
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if (n == 1) {
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return 1;
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}
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return (getLive(n - 1, m) + m - 1) % n + 1;
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}
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// 提交直接通过
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// 给定的编号是0~n-1的情况下，数到m就杀
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// 返回谁会活？
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// 这个版本是迭代版
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public int lastRemaining2(int n, int m) {
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int ans = 1;
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int r = 1;
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while (r <= n) {
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ans = (ans + m - 1) % (r++) + 1;
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}
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return ans - 1;
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}
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// 以下的code针对单链表，不要提交
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public static class Node {
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public int value;
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public Node next;
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public Node(int data) {
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this.value = data;
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}
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}
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public static Node josephusKill1(Node head, int m) {
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if (head == null || head.next == head || m < 1) {
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return head;
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}
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Node last = head;
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while (last.next != head) {
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last = last.next;
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}
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int count = 0;
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while (head != last) {
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if (++count == m) {
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last.next = head.next;
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count = 0;
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} else {
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last = last.next;
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}
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head = last.next;
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}
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return head;
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}
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public static Node josephusKill2(Node head, int m) {
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if (head == null || head.next == head || m < 1) {
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return head;
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}
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Node cur = head.next;
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int size = 1; // tmp -> list size
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while (cur != head) {
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size++;
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cur = cur.next;
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}
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int live = getLive(size, m); // tmp -> service node position
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while (--live != 0) {
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head = head.next;
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}
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head.next = head;
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return head;
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}
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public static void printCircularList(Node head) {
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if (head == null) {
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return;
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}
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System.out.print("Circular List: " + head.value + " ");
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Node cur = head.next;
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while (cur != head) {
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System.out.print(cur.value + " ");
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cur = cur.next;
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}
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System.out.println("-> " + head.value);
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}
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public static void main(String[] args) {
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Node head1 = new Node(1);
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head1.next = new Node(2);
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head1.next.next = new Node(3);
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head1.next.next.next = new Node(4);
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head1.next.next.next.next = new Node(5);
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head1.next.next.next.next.next = head1;
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printCircularList(head1);
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head1 = josephusKill1(head1, 3);
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printCircularList(head1);
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Node head2 = new Node(1);
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head2.next = new Node(2);
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head2.next.next = new Node(3);
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head2.next.next.next = new Node(4);
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head2.next.next.next.next = new Node(5);
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head2.next.next.next.next.next = head2;
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printCircularList(head2);
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head2 = josephusKill2(head2, 3);
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printCircularList(head2);
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}
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} |
