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feat: add python and java solutions to leetcode problem: No.0707
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‎README.md

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@@ -72,6 +72,7 @@
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1. [奇偶链表](/solution/0300-0399/0328.Odd%20Even%20Linked%20List/README.md)
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1. [环形链表](/solution/0100-0199/0141.Linked%20List%20Cycle/README.md)
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1. [环形链表 II](/solution/0100-0199/0142.Linked%20List%20Cycle%20II/README.md)
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1. [设计链表](/solution/0700-0799/0707.Design%20Linked%20List/README.md)
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### 二叉树
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‎README_EN.md

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@@ -70,6 +70,7 @@ Complete solutions to [LeetCode](https://leetcode-cn.com/problemset/all/), [LCOF
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1. [Odd Even Linked List](/solution/0300-0399/0328.Odd%20Even%20Linked%20List/README_EN.md)
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1. [Linked List Cycle](/solution/0100-0199/0141.Linked%20List%20Cycle/README_EN.md)
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1. [Linked List Cycle II](/solution/0100-0199/0142.Linked%20List%20Cycle%20II/README_EN.md)
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1. [Design Linked List](/solution/0700-0799/0707.Design%20Linked%20List/README_EN.md)
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### Binary Tree
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‎solution/0700-0799/0707.Design Linked List/README.md

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Original file line numberDiff line numberDiff line change
@@ -44,22 +44,184 @@ linkedList.get(1); //返回3
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<!-- 这里可写通用的实现逻辑 -->
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定义虚拟头结点 dummy，count 记录当前链表结点个数。
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<!-- tabs:start -->
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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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```python
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class ListNode:
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def __init__(self, val=0, next=None):
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self.val = val
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self.next = next
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class MyLinkedList:
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def __init__(self):
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"""
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Initialize your data structure here.
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"""
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self.dummy = ListNode()
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self.count = 0
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def get(self, index: int) -> int:
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"""
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Get the value of the index-th node in the linked list. If the index is invalid, return -1.
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"""
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if index < 0 or index >= self.count:
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return -1
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cur = self.dummy.next
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for _ in range(index):
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cur = cur.next
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return cur.val
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def addAtHead(self, val: int) -> None:
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"""
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Add a node of value val before the first element of the linked list. After the insertion, the new node will be the first node of the linked list.
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"""
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self.addAtIndex(0, val)
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def addAtTail(self, val: int) -> None:
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"""
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Append a node of value val to the last element of the linked list.
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"""
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self.addAtIndex(self.count, val)
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def addAtIndex(self, index: int, val: int) -> None:
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"""
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Add a node of value val before the index-th node in the linked list. If index equals to the length of linked list, the node will be appended to the end of linked list. If index is greater than the length, the node will not be inserted.
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"""
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if index > self.count:
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return
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pre = self.dummy
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for _ in range(index):
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pre = pre.next
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pre.next = ListNode(val, pre.next)
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self.count += 1
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def deleteAtIndex(self, index: int) -> None:
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"""
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Delete the index-th node in the linked list, if the index is valid.
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"""
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if index < 0 or index >= self.count:
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return
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pre = self.dummy
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for _ in range(index):
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pre = pre.next
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t = pre.next
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pre.next = t.next
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t.next = None
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self.count -= 1
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# Your MyLinkedList object will be instantiated and called as such:
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# obj = MyLinkedList()
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# param_1 = obj.get(index)
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# obj.addAtHead(val)
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# obj.addAtTail(val)
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# obj.addAtIndex(index,val)
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# obj.deleteAtIndex(index)
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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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```java
62-
142+
class MyLinkedList {
143+
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private class ListNode {
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int val;
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ListNode next;
147+
ListNode(int val) {
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this(val, null);
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}
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ListNode(int val, ListNode next) {
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this.val = val;
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this.next = next;
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}
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}
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private ListNode dummy;
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private int count;
158+
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/** Initialize your data structure here. */
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public MyLinkedList() {
161+
dummy = new ListNode(0);
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count = 0;
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}
164+
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/** Get the value of the index-th node in the linked list. If the index is invalid, return -1. */
166+
public int get(int index) {
167+
if (index < 0 || index >= count) {
168+
return -1;
169+
}
170+
ListNode cur = dummy.next;
171+
while (index-- > 0) {
172+
cur = cur.next;
173+
}
174+
return cur.val;
175+
}
176+
177+
/** Add a node of value val before the first element of the linked list. After the insertion, the new node will be the first node of the linked list. */
178+
public void addAtHead(int val) {
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addAtIndex(0, val);
180+
}
181+
182+
/** Append a node of value val to the last element of the linked list. */
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public void addAtTail(int val) {
184+
addAtIndex(count, val);
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}
186+
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/** Add a node of value val before the index-th node in the linked list. If index equals to the length of linked list, the node will be appended to the end of linked list. If index is greater than the length, the node will not be inserted. */
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public void addAtIndex(int index, int val) {
189+
if (index > count) {
190+
return;
191+
}
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ListNode pre = dummy;
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while (index-- > 0) {
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pre = pre.next;
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}
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pre.next = new ListNode(val, pre.next);
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++count;
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}
199+
200+
/** Delete the index-th node in the linked list, if the index is valid. */
201+
public void deleteAtIndex(int index) {
202+
if (index < 0 || index >= count) {
203+
return;
204+
}
205+
ListNode pre = dummy;
206+
while (index-- > 0) {
207+
pre = pre.next;
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}
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ListNode t = pre.next;
210+
pre.next = t.next;
211+
t.next = null;
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--count;
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}
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}
215+
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/**
217+
* Your MyLinkedList object will be instantiated and called as such:
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* MyLinkedList obj = new MyLinkedList();
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* int param_1 = obj.get(index);
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* obj.addAtHead(val);
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* obj.addAtTail(val);
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* obj.addAtIndex(index,val);
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* obj.deleteAtIndex(index);
224+
*/
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```
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### **...**

‎solution/0700-0799/0707.Design Linked List/README_EN.md

+162-2
Original file line numberDiff line numberDiff line change
@@ -53,13 +53,173 @@ linkedList.get(1);&nbsp;&nbsp;&nbsp; // returns 3
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### **Python3**
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5555
```python
56-
56+
class ListNode:
57+
58+
def __init__(self, val=0, next=None):
59+
self.val = val
60+
self.next = next
61+
62+
63+
class MyLinkedList:
64+
65+
def __init__(self):
66+
"""
67+
Initialize your data structure here.
68+
"""
69+
self.dummy = ListNode()
70+
self.count = 0
71+
72+
73+
def get(self, index: int) -> int:
74+
"""
75+
Get the value of the index-th node in the linked list. If the index is invalid, return -1.
76+
"""
77+
if index < 0 or index >= self.count:
78+
return -1
79+
cur = self.dummy.next
80+
for _ in range(index):
81+
cur = cur.next
82+
return cur.val
83+
84+
85+
def addAtHead(self, val: int) -> None:
86+
"""
87+
Add a node of value val before the first element of the linked list. After the insertion, the new node will be the first node of the linked list.
88+
"""
89+
self.addAtIndex(0, val)
90+
91+
92+
def addAtTail(self, val: int) -> None:
93+
"""
94+
Append a node of value val to the last element of the linked list.
95+
"""
96+
self.addAtIndex(self.count, val)
97+
98+
99+
def addAtIndex(self, index: int, val: int) -> None:
100+
"""
101+
Add a node of value val before the index-th node in the linked list. If index equals to the length of linked list, the node will be appended to the end of linked list. If index is greater than the length, the node will not be inserted.
102+
"""
103+
if index > self.count:
104+
return
105+
pre = self.dummy
106+
for _ in range(index):
107+
pre = pre.next
108+
pre.next = ListNode(val, pre.next)
109+
self.count += 1
110+
111+
112+
def deleteAtIndex(self, index: int) -> None:
113+
"""
114+
Delete the index-th node in the linked list, if the index is valid.
115+
"""
116+
if index < 0 or index >= self.count:
117+
return
118+
pre = self.dummy
119+
for _ in range(index):
120+
pre = pre.next
121+
t = pre.next
122+
pre.next = t.next
123+
t.next = None
124+
self.count -= 1
125+
126+
127+
128+
# Your MyLinkedList object will be instantiated and called as such:
129+
# obj = MyLinkedList()
130+
# param_1 = obj.get(index)
131+
# obj.addAtHead(val)
132+
# obj.addAtTail(val)
133+
# obj.addAtIndex(index,val)
134+
# obj.deleteAtIndex(index)
57135
```
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### **Java**
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61139
```java
62-
140+
class MyLinkedList {
141+
142+
private class ListNode {
143+
int val;
144+
ListNode next;
145+
ListNode(int val) {
146+
this(val, null);
147+
}
148+
ListNode(int val, ListNode next) {
149+
this.val = val;
150+
this.next = next;
151+
}
152+
}
153+
154+
private ListNode dummy;
155+
private int count;
156+
157+
/** Initialize your data structure here. */
158+
public MyLinkedList() {
159+
dummy = new ListNode(0);
160+
count = 0;
161+
}
162+
163+
/** Get the value of the index-th node in the linked list. If the index is invalid, return -1. */
164+
public int get(int index) {
165+
if (index < 0 || index >= count) {
166+
return -1;
167+
}
168+
ListNode cur = dummy.next;
169+
while (index-- > 0) {
170+
cur = cur.next;
171+
}
172+
return cur.val;
173+
}
174+
175+
/** Add a node of value val before the first element of the linked list. After the insertion, the new node will be the first node of the linked list. */
176+
public void addAtHead(int val) {
177+
addAtIndex(0, val);
178+
}
179+
180+
/** Append a node of value val to the last element of the linked list. */
181+
public void addAtTail(int val) {
182+
addAtIndex(count, val);
183+
}
184+
185+
/** Add a node of value val before the index-th node in the linked list. If index equals to the length of linked list, the node will be appended to the end of linked list. If index is greater than the length, the node will not be inserted. */
186+
public void addAtIndex(int index, int val) {
187+
if (index > count) {
188+
return;
189+
}
190+
ListNode pre = dummy;
191+
while (index-- > 0) {
192+
pre = pre.next;
193+
}
194+
pre.next = new ListNode(val, pre.next);
195+
++count;
196+
}
197+
198+
/** Delete the index-th node in the linked list, if the index is valid. */
199+
public void deleteAtIndex(int index) {
200+
if (index < 0 || index >= count) {
201+
return;
202+
}
203+
ListNode pre = dummy;
204+
while (index-- > 0) {
205+
pre = pre.next;
206+
}
207+
ListNode t = pre.next;
208+
pre.next = t.next;
209+
t.next = null;
210+
--count;
211+
}
212+
}
213+
214+
/**
215+
* Your MyLinkedList object will be instantiated and called as such:
216+
* MyLinkedList obj = new MyLinkedList();
217+
* int param_1 = obj.get(index);
218+
* obj.addAtHead(val);
219+
* obj.addAtTail(val);
220+
* obj.addAtIndex(index,val);
221+
* obj.deleteAtIndex(index);
222+
*/
63223
```
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### **...**

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