complete the pset

semester2/pset1/3-appendLinkedList.c

@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct link {
+  int data;
+  struct link *next;
+} * Link;
+
+Link AppendNode(Link head, int data);
+void DisplyNode(Link head);
+
+int main() {
+  int data;
+  Link head = NULL;
+  while (1) {
+    scanf("%d", &data);
+    if (data == -1)
+      break;
+    head = AppendNode(head, data);
+  }
+  if (head != NULL)
+    DisplyNode(head);
+  else
+    printf("NULL");
+
+  return 0;
+}
+
+/*在此实现 AppendNode函数 */
+Link AppendNode(Link head, int data) {
+
+  if (head == NULL) {
+    head = malloc(sizeof(Link));
+    head->next = NULL;
+    head->data = data;
+  } else {
+    Link ptr = head;
+    while (ptr->next != NULL) {
+      ptr = ptr->next;
+    }
+
+    Link next = malloc(sizeof(Link));
+    ptr->next = next;
+    next->next = NULL;
+    next->data = data;
+  }
+
+  return head;
+}
+
+/*在此实现DisplyNode函数 */
+void DisplyNode(Link head) {
+  printf("%d", head->data);
+  Link ptr = head->next;
+
+  while (ptr != NULL) {
+    printf(",%d", ptr->data);
+    ptr = ptr->next;
+  }
+}

semester2/pset1/4-Joseph.c

@@ -0,0 +1,102 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct Node {
+  // Clockwise order
+  struct Node *next;
+  // Anti clockwise order
+  struct Node *prev;
+  // Starts from 1, clockwise
+  int id;
+} Node;
+
+Node *constructRing(int len);
+Node *appendNode(Node *head, int id);
+Node *deleteNode(Node *head, int direction);
+Node *iterateNode(Node *head, int direction,
+                  int count); // 1: clockwise, 0: anti clockwise
+
+int main(void) {
+  int n, m, k;
+  scanf("%d%d%d", &n, &m, &k);
+
+  Node *head = constructRing(n);
+
+  int count = 0;
+  for (int i = 0; i < n; i++) {
+
+    // determine the count
+    if (i % 2 == 0) { // Anti clockwise
+      count = m;
+    } else {
+      count = k;
+    }
+
+    head = iterateNode(head, i % 2, count);
+
+    printf("%d ", head->id);
+    head = deleteNode(head, i % 2);
+  }
+
+  return 0;
+}
+
+Node *constructRing(int len) {
+  // Construct the first node
+  Node *head = malloc(sizeof(Node));
+  head->id = 1;
+  head->prev = NULL;
+  head->next = NULL;
+
+  Node *ptr = head;
+
+  for (int i = 2; i <= len; i++) {
+    ptr = appendNode(ptr, i);
+  }
+  ptr->next = head;
+	head->prev = ptr;
+
+  return head;
+}
+
+Node *appendNode(Node *head, int id) {
+  Node *new = malloc(sizeof(Node));
+  new->id = id;
+  new->prev = head;
+  new->next = NULL; // Can be deleted
+
+  head->next = new;
+  return new;
+}
+
+Node *deleteNode(Node *head, int direction) {
+  Node *prev = head->prev;
+  Node *next = head->next;
+
+	if (head == next) {// Single element in the ring
+		free(head);
+		return NULL;
+	}
+
+  prev->next = next;
+  next->prev = prev;
+  free(head);
+
+  if (direction == 1)
+    return next;
+  else
+    return prev;
+}
+
+Node *iterateNode(Node *head, int direction,
+                  int count) { // 1: clockwise, 0: anti clockwise
+  Node *ptr = head;
+  for (int i = 1; i < count; i++) { // starts from 1
+    if (direction == 1)
+      ptr = ptr->next;
+    else
+      ptr = ptr->prev;
+  }
+
+  return ptr;
+}