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feat: add solutions to lcof2 problems: No.024,025,026
1 parent 988142c commit 896885a

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-6
lines changed

16 files changed

+755
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‎lcof2/剑指 Offer II 024. 反转链表/README.md

+105-4
Original file line numberDiff line numberDiff line change
@@ -59,18 +59,119 @@
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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6462
```python
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# Definition for singly-linked list.
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# class ListNode:
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# def __init__(self, x):
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# self.val = x
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# self.next = None
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class Solution:
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def reverseList(self, head: ListNode) -> ListNode:
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pre, p = None, head
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while p:
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q = p.next
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p.next = pre
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pre = p
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p = q
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return pre
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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迭代版本：
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```java
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/**
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* Definition for singly-linked list.
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* public class ListNode {
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* int val;
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* ListNode next;
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* ListNode(int x) { val = x; }
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* }
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*/
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class Solution {
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public ListNode reverseList(ListNode head) {
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ListNode pre = null, p = head;
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while (p != null) {
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ListNode q = p.next;
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p.next = pre;
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pre = p;
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p = q;
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}
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return pre;
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}
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}
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```
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递归版本：
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```java
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/**
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* Definition for singly-linked list.
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* public class ListNode {
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* int val;
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* ListNode next;
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* ListNode(int x) { val = x; }
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* }
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*/
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class Solution {
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public ListNode reverseList(ListNode head) {
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if (head == null || head.next == null) {
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return head;
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}
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ListNode res = reverseList(head.next);
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head.next.next = head;
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head.next = null;
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return res;
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}
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}
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```
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### **JavaScript**
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```js
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/**
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* Definition for singly-linked list.
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* function ListNode(val) {
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* this.val = val;
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* this.next = null;
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* }
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*/
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/**
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* @param {ListNode} head
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* @return {ListNode}
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*/
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var reverseList = function (head) {
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let node = head;
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let pre = null;
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while (node) {
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let cur = node;
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node = cur.next;
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cur.next = pre;
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pre = cur;
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}
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return pre;
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};
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```
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### **Go**
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```go
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func reverseList(head *ListNode) *ListNode {
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if head == nil ||head.Next == nil {
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return head
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}
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dummyHead := &ListNode{}
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cur := head
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for cur != nil {
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tmp := cur.Next
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cur.Next = dummyHead.Next
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dummyHead.Next = cur
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cur = tmp
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}
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return dummyHead.Next
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}
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```
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### **...**

‎lcof2/剑指 Offer II 024. 反转链表/Solution.cs

+13
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
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public class Solution {
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public ListNode ReverseList(ListNode head) {
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ListNode newHead = null;
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while (head != null)
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{
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var next = head.next;
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head.next = newHead;
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newHead = head;
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head = next;
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}
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return newHead;
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}
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}

‎lcof2/剑指 Offer II 024. 反转链表/Solution.go

+14
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
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func reverseList(head *ListNode) *ListNode {
2+
if head == nil ||head.Next == nil {
3+
return head
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}
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dummyHead := &ListNode{}
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cur := head
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for cur != nil {
8+
tmp := cur.Next
9+
cur.Next = dummyHead.Next
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dummyHead.Next = cur
11+
cur = tmp
12+
}
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return dummyHead.Next
14+
}

‎lcof2/剑指 Offer II 024. 反转链表/Solution.java

+20
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,20 @@
1+
/**
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* Definition for singly-linked list.
3+
* public class ListNode {
4+
* int val;
5+
* ListNode next;
6+
* ListNode(int x) { val = x; }
7+
* }
8+
*/
9+
class Solution {
10+
public ListNode reverseList(ListNode head) {
11+
ListNode pre = null, p = head;
12+
while (p != null) {
13+
ListNode q = p.next;
14+
p.next = pre;
15+
pre = p;
16+
p = q;
17+
}
18+
return pre;
19+
}
20+
}

‎lcof2/剑指 Offer II 024. 反转链表/Solution.js

+22
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,22 @@
1+
/**
2+
* Definition for singly-linked list.
3+
* function ListNode(val) {
4+
* this.val = val;
5+
* this.next = null;
6+
* }
7+
*/
8+
/**
9+
* @param {ListNode} head
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* @return {ListNode}
11+
*/
12+
var reverseList = function (head) {
13+
let node = head;
14+
let pre = null;
15+
while (node) {
16+
let cur = node;
17+
node = cur.next;
18+
cur.next = pre;
19+
pre = cur;
20+
}
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return pre;
22+
};

‎lcof2/剑指 Offer II 024. 反转链表/Solution.py

+15
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
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# Definition for singly-linked list.
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# class ListNode:
3+
# def __init__(self, x):
4+
# self.val = x
5+
# self.next = None
6+
7+
class Solution:
8+
def reverseList(self, head: ListNode) -> ListNode:
9+
pre, p = None, head
10+
while p:
11+
q = p.next
12+
p.next = pre
13+
pre = p
14+
p = q
15+
return pre

‎lcof2/剑指 Offer II 025. 链表中的两数相加/README.md

+94-1
Original file line numberDiff line numberDiff line change
@@ -56,22 +56,115 @@
5656

5757
<!-- 这里可写通用的实现逻辑 -->
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59+
利用栈将数字逆序。
60+
5961
<!-- tabs:start -->
6062

6163
### **Python3**
6264

6365
<!-- 这里可写当前语言的特殊实现逻辑 -->
6466

6567
```python
66-
68+
# Definition for singly-linked list.
69+
# class ListNode:
70+
# def __init__(self, x):
71+
# self.val = x
72+
# self.next = None
73+
74+
class Solution:
75+
def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
76+
s1, s2 = [], []
77+
while l1:
78+
s1.append(l1.val)
79+
l1 = l1.next
80+
while l2:
81+
s2.append(l2.val)
82+
l2 = l2.next
83+
carry, dummy = 0, ListNode(-1)
84+
while s1 or s2 or carry:
85+
carry += (0 if not s1 else s1.pop()) + (0 if not s2 else s2.pop())
86+
# 创建结点，利用头插法将结点插入链表
87+
node = ListNode(carry % 10)
88+
node.next = dummy.next
89+
dummy.next = node
90+
carry //= 10
91+
return dummy.next
6792
```
6893

6994
### **Java**
7095

7196
<!-- 这里可写当前语言的特殊实现逻辑 -->
7297

7398
```java
99+
/**
100+
* Definition for singly-linked list.
101+
* public class ListNode {
102+
* int val;
103+
* ListNode next;
104+
* ListNode(int x) { val = x; }
105+
* }
106+
*/
107+
class Solution {
108+
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
109+
Deque<Integer> s1 = new ArrayDeque<>();
110+
Deque<Integer> s2 = new ArrayDeque<>();
111+
for (; l1 != null; l1 = l1.next) {
112+
s1.push(l1.val);
113+
}
114+
for (; l2 != null; l2 = l2.next) {
115+
s2.push(l2.val);
116+
}
117+
int carry = 0;
118+
ListNode dummy = new ListNode(-1);
119+
while (!s1.isEmpty() || !s2.isEmpty() || carry != 0) {
120+
carry += (s1.isEmpty() ? 0 : s1.pop()) + (s2.isEmpty() ? 0 : s2.pop());
121+
// 创建结点，利用头插法将结点插入链表
122+
ListNode node = new ListNode(carry % 10);
123+
node.next = dummy.next;
124+
dummy.next = node;
125+
carry /= 10;
126+
}
127+
return dummy.next;
128+
}
129+
}
130+
```
74131

132+
### **Go**
133+
134+
```go
135+
/**
136+
* Definition for singly-linked list.
137+
* type ListNode struct {
138+
* Val int
139+
* Next *ListNode
140+
* }
141+
*/
142+
func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
143+
s1, s2 := arraystack.New(), arraystack.New()
144+
for l1 != nil {
145+
s1.Push(l1.Val)
146+
l1 = l1.Next
147+
}
148+
for l2 != nil {
149+
s2.Push(l2.Val)
150+
l2 = l2.Next
151+
}
152+
carry, dummy := 0, new(ListNode)
153+
for !s1.Empty() || !s2.Empty() || carry > 0 {
154+
v, ok := s1.Pop()
155+
if ok {
156+
carry += v.(int)
157+
}
158+
v, ok = s2.Pop()
159+
if ok {
160+
carry += v.(int)
161+
}
162+
node := &ListNode{Val: carry % 10, Next: dummy.Next}
163+
dummy.Next = node
164+
carry /= 10
165+
}
166+
return dummy.Next
167+
}
75168
```
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77170
### **...**

‎lcof2/剑指 Offer II 025. 链表中的两数相加/Solution.go

+33
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,33 @@
1+
/**
2+
* Definition for singly-linked list.
3+
* type ListNode struct {
4+
* Val int
5+
* Next *ListNode
6+
* }
7+
*/
8+
func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
9+
s1, s2 := arraystack.New(), arraystack.New()
10+
for l1 != nil {
11+
s1.Push(l1.Val)
12+
l1 = l1.Next
13+
}
14+
for l2 != nil {
15+
s2.Push(l2.Val)
16+
l2 = l2.Next
17+
}
18+
carry, dummy := 0, new(ListNode)
19+
for !s1.Empty() || !s2.Empty() || carry > 0 {
20+
v, ok := s1.Pop()
21+
if ok {
22+
carry += v.(int)
23+
}
24+
v, ok = s2.Pop()
25+
if ok {
26+
carry += v.(int)
27+
}
28+
node := &ListNode{Val: carry % 10, Next: dummy.Next}
29+
dummy.Next = node
30+
carry /= 10
31+
}
32+
return dummy.Next
33+
}

‎lcof2/剑指 Offer II 025. 链表中的两数相加/Solution.java

+30
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,30 @@
1+
/**
2+
* Definition for singly-linked list.
3+
* public class ListNode {
4+
* int val;
5+
* ListNode next;
6+
* ListNode(int x) { val = x; }
7+
* }
8+
*/
9+
class Solution {
10+
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
11+
Deque<Integer> s1 = new ArrayDeque<>();
12+
Deque<Integer> s2 = new ArrayDeque<>();
13+
for (; l1 != null; l1 = l1.next) {
14+
s1.push(l1.val);
15+
}
16+
for (; l2 != null; l2 = l2.next) {
17+
s2.push(l2.val);
18+
}
19+
int carry = 0;
20+
ListNode dummy = new ListNode(-1);
21+
while (!s1.isEmpty() || !s2.isEmpty() || carry != 0) {
22+
carry += (s1.isEmpty() ? 0 : s1.pop()) + (s2.isEmpty() ? 0 : s2.pop());
23+
ListNode node = new ListNode(carry % 10);
24+
node.next = dummy.next;
25+
dummy.next = node;
26+
carry /= 10;
27+
}
28+
return dummy.next;
29+
}
30+
}

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