Problem description

Josephus ring (Josephus problem) is a mathematical application problem: known n individuals (represented by numbers 1, 2, 3...n respectively) sit around a round table clockwise, each holding a password (positive integer). At the beginning, select an integer as the upper limit value m of the report, report clockwise from the first person, stop reporting when reporting to m, the person reporting m will be listed, his password will be the new m value, and the next person reporting to m in the clockwise direction will be listed again from 1, and the person reporting to m will be listed again; repeat this rule until all the people around the round table are listed.

Input format

Number n in the first line indicates the number of people in the round table;
The second line is n integers, indicating the password held by the guests in the round table:
The third line is an integer, representing the initial m value;

Output format

The order in which people leave the table

sample input

sample output

Solving problems

This problem only needs to pay attention to the head node of the linked list when it is looped.

code implementation

#include <stdio.h>
#include <stdlib.h>

typedef struct Node {
	int data;
	int index;
	struct Node *next;
} Node, *LinkList;

void initLink(LinkList *link);
void create(LinkList link, int size);
int main(int argc, char *argv[]) {
	int m = 0, n = 0, count = 1, sum = 0;
	// Pointer p points to the position when the number is reported, and pointer q points to the previous bit when the number is reported
	Node *p, *q;
	scanf("%d", &n);
	LinkList link;
	initLink(&link);
	create(link, n);
	scanf("%d", &m);
	p = link->next;
	while (sum != n) {
		if (count == m) {
			printf("%d\t", p->index);
			m = p->data;
			q->next = p->next;
			free(p);
			p = q->next;
			count = 0;
			sum++;
		} else {
			q = p;
			p = p->next;
		}
		// When the pointer p points to the head pointer of the linked list, the pointer moves backward one bit
		if (p->index == -1) {
			q = p;
			p = p->next;
		}
		count++;
	}
	return 0;
}

void initLink(LinkList *link) {
	*link = (LinkList)malloc(sizeof(Node));
	(*link)->next = NULL;
	(*link)->index = -1;
}

void create(LinkList link, int size) {
	int i;
	Node *node, *q;
	q = link;
	for (i = 0; i < size; i++) {
		node = (Node *)malloc(sizeof(Node));
		scanf("%d", &node->data);
		node->index = i + 1;
		link->next = node;
		link = node;
	}
	link->next = q;
}