Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly
Sign up
Appearance settings

[pull] master from youngyangyang04:master #5

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
pull merged 9 commits into AlgorithmAndLeetCode:master from youngyangyang04:master
May 30, 2022
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
18 changes: 18 additions & 0 deletions problems/0001.两数之和.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -274,6 +274,24 @@ class Solution {
}
}
```
C#:
```csharp
public class Solution {
public int[] TwoSum(int[] nums, int target) {
Dictionary<int ,int> dic= new Dictionary<int,int>();
for(int i=0;i<nums.Length;i++){
int imp= target-nums[i];
if(dic.ContainsKey(imp)&&dic[imp]!=i){
return new int[]{i, dic[imp]};
}
if(!dic.ContainsKey(nums[i])){
dic.Add(nums[i],i);
}
}
return new int[]{0, 0};
}
}
```

-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
24 changes: 23 additions & 1 deletion problems/0019.删除链表的倒数第N个节点.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -289,6 +289,28 @@ func removeNthFromEnd(_ head: ListNode?, _ n: Int) -> ListNode? {
return dummyHead.next
}
```

Scala:
```scala
object Solution {
def removeNthFromEnd(head: ListNode, n: Int): ListNode = {
val dummy = new ListNode(-1, head) // 定义虚拟头节点
var fast = head // 快指针从头开始走
var slow = dummy // 慢指针从虚拟头开始头
// 因为参数 n 是不可变量,所以不能使用 while(n>0){n-=1}的方式
for (i <- 0 until n) {
fast = fast.next
}
// 快指针和满指针一起走,直到fast走到null
while (fast != null) {
slow = slow.next
fast = fast.next
}
// 删除slow的下一个节点
slow.next = slow.next.next
// 返回虚拟头节点的下一个
dummy.next
}
}
```
-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
24 changes: 23 additions & 1 deletion problems/0024.两两交换链表中的节点.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -311,7 +311,29 @@ func swapPairs(_ head: ListNode?) -> ListNode? {
return dummyHead.next
}
```

Scala:
```scala
// 虚拟头节点
object Solution {
def swapPairs(head: ListNode): ListNode = {
var dummy = new ListNode(0, head) // 虚拟头节点
var pre = dummy
var cur = head
// 当pre的下一个和下下个都不为空,才进行两两转换
while (pre.next != null && pre.next.next != null) {
var tmp: ListNode = cur.next.next // 缓存下一次要进行转换的第一个节点
pre.next = cur.next // 步骤一
cur.next.next = cur // 步骤二
cur.next = tmp // 步骤三
// 下面是准备下一轮的交换
pre = cur
cur = tmp
}
// 最终返回dummy虚拟头节点的下一个,return可以省略
dummy.next
}
}
```

-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
23 changes: 23 additions & 0 deletions problems/0202.快乐数.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -385,5 +385,28 @@ bool isHappy(int n){
return bHappy;
}
```

C#:
```csharp
public class Solution {
private int getSum(int n) {
int sum = 0;
//每位数的换算
while (n > 0) {
sum += (n % 10) * (n % 10);
n /= 10;
}
return sum;
}
public bool IsHappy(int n) {
HashSet <int> set = new HashSet<int>();
while(n != 1 && !set.Contains(n)) { //判断避免循环
set.Add(n);
n = getSum(n);
}
return n == 1;
}
}
```
-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
34 changes: 34 additions & 0 deletions problems/0206.翻转链表.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -496,6 +496,40 @@ struct ListNode* reverseList(struct ListNode* head){
return reverse(NULL, head);
}
```
Scala:

双指针法:
```scala
object Solution {
def reverseList(head: ListNode): ListNode = {
var pre: ListNode = null
var cur = head
while (cur != null) {
var tmp = cur.next
cur.next = pre
pre = cur
cur = tmp
}
pre
}
}
```
递归法:
```scala
object Solution {
def reverseList(head: ListNode): ListNode = {
reverse(null, head)
}

def reverse(pre: ListNode, cur: ListNode): ListNode = {
if (cur == null) {
return pre // 如果当前cur为空,则返回pre
}
val tmp: ListNode = cur.next
cur.next = pre
reverse(cur, tmp) // 此时cur成为前一个节点,tmp是当前节点
}
}
```
-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
19 changes: 19 additions & 0 deletions problems/0242.有效的字母异位词.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -307,6 +307,25 @@ impl Solution {
}
}
```

C#:
```csharp
public bool IsAnagram(string s, string t) {
int sl=s.Length,tl=t.Length;
if(sl!=tl) return false;
int[] a = new int[26];
for(int i = 0; i < sl; i++){
a[s[i] - 'a']++;
a[t[i] - 'a']--;
}
foreach (int i in a)
{
if (i != 0)
return false;
}
return true;
}
```
## 相关题目

* 383.赎金信
Expand Down
18 changes: 18 additions & 0 deletions problems/0349.两个数组的交集.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -313,6 +313,24 @@ int* intersection1(int* nums1, int nums1Size, int* nums2, int nums2Size, int* re
}
```

C#:
```csharp
public int[] Intersection(int[] nums1, int[] nums2) {
if(nums1==null||nums1.Length==0||nums2==null||nums1.Length==0)
return new int[0]; //注意数组条件
HashSet<int> one = Insert(nums1);
HashSet<int> two = Insert(nums2);
one.IntersectWith(two);
return one.ToArray();
}
public HashSet<int> Insert(int[] nums){
HashSet<int> one = new HashSet<int>();
foreach(int num in nums){
one.Add(num);
}
return one;
}
```
## 相关题目

* 350.两个数组的交集 II
Expand Down
17 changes: 17 additions & 0 deletions problems/0383.赎金信.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -363,5 +363,22 @@ impl Solution {
}
```

C#:
```csharp
public bool CanConstruct(string ransomNote, string magazine) {
if(ransomNote.Length > magazine.Length) return false;
int[] letters = new int[26];
foreach(char c in magazine){
letters[c-'a']++;
}
foreach(char c in ransomNote){
letters[c-'a']--;
if(letters[c-'a']<0){
return false;
}
}
return true;
}
```
-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
27 changes: 27 additions & 0 deletions problems/0454.四数相加II.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -318,5 +318,32 @@ impl Solution {
}
```

C#:
```csharp
public int FourSumCount(int[] nums1, int[] nums2, int[] nums3, int[] nums4) {
Dictionary<int, int> dic = new Dictionary<int, int>();
foreach(var i in nums1){
foreach(var j in nums2){
int sum = i + j;
if(dic.ContainsKey(sum)){
dic[sum]++;
}else{
dic.Add(sum, 1);
}

}
}
int res = 0;
foreach(var a in nums3){
foreach(var b in nums4){
int sum = a+b;
if(dic.TryGetValue(-sum, out var result)){
res += result;
}
}
}
return res;
}
```
-----------------------
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
68 changes: 68 additions & 0 deletions problems/0707.设计链表.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1154,7 +1154,75 @@ class MyLinkedList {
}
```

Scala:
```scala
class ListNode(_x: Int = 0, _next: ListNode = null) {
var next: ListNode = _next
var x: Int = _x
}

class MyLinkedList() {

var size = 0 // 链表尺寸
var dummy: ListNode = new ListNode(0) // 虚拟头节点

// 获取第index个节点的值
def get(index: Int): Int = {
if (index < 0 || index >= size) {
return -1;
}
var cur = dummy
for (i <- 0 to index) {
cur = cur.next
}
cur.x // 返回cur的值
}

// 在链表最前面插入一个节点
def addAtHead(`val`: Int) {
addAtIndex(0, `val`)
}

// 在链表最后面插入一个节点
def addAtTail(`val`: Int) {
addAtIndex(size, `val`)
}

// 在第index个节点之前插入一个新节点
// 如果index等于链表长度,则说明新插入的节点是尾巴
// 如果index等于0,则说明新插入的节点是头
// 如果index>链表长度,则说明为空
def addAtIndex(index: Int, `val`: Int) {
if (index > size) {
return
}
var loc = index // 因为参数index是val不可变类型,所以需要赋值给一个可变类型
if (index < 0) {
loc = 0
}
size += 1 //链表尺寸+1
var pre = dummy
for (i <- 0 until loc) {
pre = pre.next
}
val node: ListNode = new ListNode(`val`, pre.next)
pre.next = node
}
// 删除第index个节点
def deleteAtIndex(index: Int) {
if (index < 0 || index >= size) {
return
}
size -= 1
var pre = dummy
for (i <- 0 until index) {
pre = pre.next
}
pre.next = pre.next.next
}

}
```


-----------------------
Expand Down
50 changes: 49 additions & 1 deletion problems/面试题02.07.链表相交.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -317,7 +317,55 @@ ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
}
```


Scala:
```scala
object Solution {
def getIntersectionNode(headA: ListNode, headB: ListNode): ListNode = {
var lenA = 0 // headA链表的长度
var lenB = 0 // headB链表的长度
var tmp = headA // 临时变量
// 统计headA的长度
while (tmp != null) {
lenA += 1;
tmp = tmp.next
}
// 统计headB的长度
tmp = headB // 临时变量赋值给headB
while (tmp != null) {
lenB += 1
tmp = tmp.next
}
// 因为传递过来的参数是不可变量,所以需要重新定义
var listA = headA
var listB = headB
// 两个链表的长度差
// 如果gap>0,lenA>lenB,headA(listA)链表往前移动gap步
// 如果gap<0,lenA<lenB,headB(listB)链表往前移动-gap步
var gap = lenA - lenB
if (gap > 0) {
// 因为不可以i-=1,所以可以使用for
for (i <- 0 until gap) {
listA = listA.next // 链表headA(listA) 移动
}
} else {
gap = math.abs(gap) // 此刻gap为负值,取绝对值
for (i <- 0 until gap) {
listB = listB.next
}
}
// 现在两个链表同时往前走,如果相等则返回
while (listA != null && listB != null) {
if (listA == listB) {
return listA
}
listA = listA.next
listB = listB.next
}
// 如果链表没有相交则返回null,return可以省略
null
}
}
```


-----------------------
Expand Down

AltStyle によって変換されたページ (->オリジナル) /