From f4cd8296df7ae469dbc010b8b4377b43aa751f5c Mon Sep 17 00:00:00 2001
From: begeekmyfriend <begeekmyfriend@gmail.com>
Date: Tue, 22 Aug 2017 11:14:22 +0800
Subject: [PATCH] Reverse linked list

Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>
---
 092_reverse_linked_list_ii/Makefile       |  2 +
 092_reverse_linked_list_ii/reverse_list.c | 60 +++++++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 092_reverse_linked_list_ii/Makefile
 create mode 100644 092_reverse_linked_list_ii/reverse_list.c

diff --git a/092_reverse_linked_list_ii/Makefile b/092_reverse_linked_list_ii/Makefile
new file mode 100644
index 0000000..d480ecf
--- /dev/null
+++ b/092_reverse_linked_list_ii/Makefile
@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test reverse_list.c
diff --git a/092_reverse_linked_list_ii/reverse_list.c b/092_reverse_linked_list_ii/reverse_list.c
new file mode 100644
index 0000000..a3d5815
--- /dev/null
+++ b/092_reverse_linked_list_ii/reverse_list.c
@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+struct ListNode {
+    int val;
+    struct ListNode *next;
+};
+
+static struct ListNode* reverseBetween(struct ListNode* head, int m, int n)
+{
+    int len = n - m + 1;
+    if (len == 1) {
+        return head;
+    }
+
+    struct ListNode dummy;
+    struct ListNode *p = head;
+    struct ListNode *prev = &dummy;
+    prev->next = p;
+    while (--m > 0) {
+        prev = p;
+        p = p->next;
+    }
+
+    struct ListNode *q = p->next;
+    while (--len > 0) {
+        p->next = q->next;
+        q->next = prev->next;
+        prev->next = q;
+        q = p->next;
+    }
+    return dummy.next;
+}
+
+int main(int argc, char **argv)
+{
+    if (argc < 3) {
+        fprintf(stderr, "Usage: ./test m n 1 2 3...\n");
+        exit(-1);
+    }
+    int i, count = argc - 3;
+    struct ListNode dummy;
+    struct ListNode *prev = &dummy;
+    struct ListNode *p;
+    for (i = 0; i < count; i++) {
+        p = malloc(sizeof(*p));
+        p->val = atoi(argv[i + 3]);
+        p->next = NULL;
+        prev->next = p;
+        prev = p;
+    }
+    int m = atoi(argv[1]);
+    int n = atoi(argv[2]);
+    struct ListNode *head = reverseBetween(dummy.next, m, n);
+    for (p = head; p != NULL; p = p->next) {
+        printf("%d ", p->val);
+    }
+    printf("\n");
+    return 0;
+}