-
Notifications
You must be signed in to change notification settings - Fork 0
/
25_Reverse_Nodes_in_k-Group.cpp
92 lines (85 loc) · 2.46 KB
/
25_Reverse_Nodes_in_k-Group.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
#include<bits/stdc++.h>
using namespace std;
struct ListNode {
int val;
ListNode *next;
ListNode() : val(0), next(nullptr) {}
ListNode(int x) : val(x), next(nullptr) {}
ListNode(int x, ListNode *next) : val(x), next(next) {}
};
void print(ListNode * head) {
while(head != NULL) {
cout << head->val << ' ';
head = head->next;
}
cout<<endl;
}
class Solution {
public:
ListNode* reverseKGroup(ListNode* head, int k) {
if(k==1) return head;
if(head == NULL || head->next == NULL) return head;
ListNode * prev = head;
ListNode * subHead = head->next;
head->next = NULL;
int temp = k-1;
while(subHead != NULL && temp--) {
ListNode * next = subHead->next;
subHead->next = head;
head = subHead;
subHead = next;
}
ListNode * next;
while(subHead != NULL) {
temp = k-1;
ListNode * tempNode = subHead;
while(temp-- && tempNode != NULL) tempNode = tempNode->next;
if(tempNode == NULL) {
prev->next = subHead;
return head;
}
else {
temp = k-1;
tempNode = subHead;
}
ListNode * curr = tempNode->next;
tempNode->next = NULL;
if(curr == NULL) next = NULL;
while(temp-- && curr != NULL) {
next = curr->next;
curr->next = tempNode;
tempNode = curr;
curr = next;
}
prev->next = tempNode;
prev = subHead;
subHead = next;
}
return head;
}
};
int main() {
Solution s;
ListNode * head = new ListNode(1);
ListNode * tempNode = head;
tempNode->next = new ListNode(2);
tempNode = tempNode->next;
tempNode->next = new ListNode(3);
tempNode = tempNode->next;
tempNode->next = new ListNode(4);
tempNode = tempNode->next;
tempNode->next = new ListNode(5);
tempNode = tempNode->next;
tempNode->next = new ListNode(6);
tempNode = tempNode->next;
tempNode->next = new ListNode(7);
tempNode = tempNode->next;
tempNode->next = new ListNode(8);
tempNode = tempNode->next;
tempNode->next = new ListNode(9);
tempNode = tempNode->next;
tempNode->next = new ListNode(10);
print(head);
head = s.reverseKGroup(head, 3);
print(head);
}