From 6385d6a2ec6498bd6e9bebf1cc09d8f2037baf9b Mon Sep 17 00:00:00 2001
From: Leo Ma <begeekmyfriend@gmail.com>
Date: Sat, 5 Aug 2017 07:11:12 +0800
Subject: [PATCH] Rotate list

Signed-off-by: Leo Ma <begeekmyfriend@gmail.com>
---
 061_rotate_list/Makefile      |  2 +
 061_rotate_list/rotate_list.c | 77 +++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)
 create mode 100644 061_rotate_list/Makefile
 create mode 100644 061_rotate_list/rotate_list.c

diff --git a/061_rotate_list/Makefile b/061_rotate_list/Makefile
new file mode 100644
index 0000000..dd0aef9
--- /dev/null
+++ b/061_rotate_list/Makefile
@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test rotate_list.c
diff --git a/061_rotate_list/rotate_list.c b/061_rotate_list/rotate_list.c
new file mode 100644
index 0000000..5e84ef5
--- /dev/null
+++ b/061_rotate_list/rotate_list.c
@@ -0,0 +1,77 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+struct ListNode {
+    int val;
+    struct ListNode *next;
+};
+
+static struct ListNode* rotateRight(struct ListNode* head, int k) {
+    if (head == NULL || k <= 0) {
+        return head;
+    }
+
+    struct ListNode dummy;
+    dummy.next = head;
+    struct ListNode *prev = &dummy;
+    struct ListNode *last = &dummy;
+    struct ListNode *p = head;
+    int count = k;
+    while (k > 0) {
+        if (p == NULL) {
+            int length = count - k;
+            prev = &dummy;
+            p = head;
+            k = count % length;
+            if (k == 0) break;
+        }
+        prev = p;
+        p = p->next;
+        k--;
+    }
+
+    while (p != NULL) {
+        last = last->next;
+        prev = p;
+        p = p->next;
+    }
+
+    if (last != &dummy) {
+        prev->next = head;
+        dummy.next = last->next;
+        last->next = NULL;
+    }
+    return dummy.next;
+}
+
+int main(int argc, char **argv)
+{
+    int i;
+    struct ListNode *p, *prev, dummy, *list;
+
+    if (argc < 2) {
+        fprintf(stderr, "Usage: ./test k n1 n2...\n");
+        exit(-1);
+    }
+
+    dummy.next = NULL;
+    prev = &dummy;
+    for (i = 2; i < argc; i++) {
+        p = malloc(sizeof(*p));
+        int n = atoi(argv[i]);
+        printf("%d ", n);
+        p->val = n;
+        p->next = NULL;
+        prev->next = p;
+        prev = p;
+    }
+    putchar('\n');
+
+    list = rotateRight(dummy.next, atoi(argv[1]));
+    for (p = list; p != NULL; p = p->next) {
+        printf("%d ", p->val);
+    }
+    putchar('\n');
+
+    return 0;
+}