Add Josephus Problem Using Circular Linked List (#86)

* Add Josephus Problem Using Circular Linked List

* Update josephus-problem.c

Made all requested changes

linked-lists/README.md

@@ -14,6 +14,8 @@
 3. [Circular Linked List](c-or-cpp/circular.cpp)
 4. [Insertion Linked List](c-or-cpp/all-possible-insertion.cpp)
 
+4. [Josephus Problem Using Circular Linked List](c-or-cpp/josephus-problem.c)
+
 ### Java
 
 1. [Singly Linked List](java/singly.cpp)

linked-lists/c-or-cpp/josephus-problem.c

@@ -0,0 +1,77 @@
+/*Circular linked list implementation in C Programming
+has been used to solve this problem
+
+Problem :
+People are standing in a circle waiting to be executed. 
+Counting begins at a specified point in the circle and proceeds around 
+the circle in a specified direction. The problem is to find the person standing at which position
+survives at the end, who is then deemed to be the winner.
+
+*/
+#include <stdio.h>
+#include <stdlib.h>
+struct Node{
+    int data;
+    struct Node *next;
+}*first,*last;
+void create (int a[],int n){// for creating nodes
+    struct Node *t;
+    first=(struct Node*)malloc(sizeof(struct Node));
+    first->data=a[0];
+    first->next=NULL;
+    last=first;
+    for(int i=1;i<n;i++){
+        t=(struct Node*)malloc(sizeof(struct Node));
+        t->data=a[i];
+        t->next=NULL;
+        last->next=t;
+        last=t;
+    }
+    last->next=first;
+
+}
+void display(struct Node *p){ //displaying nodes
+ printf("The Linked List is successfully created\n");
+   while(p->next!=first){
+       printf("->%d",p->data);
+       p=p->next;
+   }
+   printf("->%d",p->data);
+}
+void josephus(int k, struct Node *first){ //josephus implementation
+    struct Node *trail;
+    if (k==1){
+       printf("The Winner is the person standing at= %d",last->data); 
+    }
+    else{
+    while(first->next!=first){
+        int count=1;
+        while(count!=k){
+        trail=first;
+        first=first->next;
+        count++;
+        }
+      trail->next=first->next;
+      free(first);
+      first=trail->next;
+    }
+    printf("The Winner is the person standing at= %d",first->data);
+    }
+}
+int main() {
+   int n,a[100],k;
+   printf("Enter the number of people in the circle : ");
+   scanf("%d",&n);
+   printf("Enter their positions in the circle: ");
+    for (int i=0;i<n;i++){
+        scanf("%d",&a[i]);
+    }
+    create(a,n);
+    display(first);
+    printf("\n");
+    printf("Enter the number of skips: ");
+    scanf("%d",&k);
+    josephus(k,first);
+   
+    return 0;
+}