diff --git a/problems/0024.两两交换链表中的节点.md b/problems/0024.两两交换链表中的节点.md index 36f9b0cc..57034f47 100644 --- a/problems/0024.两两交换链表中的节点.md +++ b/problems/0024.两两交换链表中的节点.md @@ -459,6 +459,40 @@ impl Solution { } ``` +### C# +```C# +// 虚拟头结点 +public ListNode SwapPairs(ListNode head) +{ + var dummyHead = new ListNode(); + dummyHead.next = head; + ListNode cur = dummyHead; + while (cur.next != null && cur.next.next != null) + { + ListNode tmp1 = cur.next; + ListNode tmp2 = cur.next.next.next; + + cur.next = cur.next.next; + cur.next.next = tmp1; + cur.next.next.next = tmp2; + + cur = cur.next.next; + } + return dummyHead.next; +} +``` +``` C# +// 递归 +public ListNode SwapPairs(ListNode head) +{ + if (head == null || head.next == null) return head; + var cur = head.next; + head.next = SwapPairs(head.next.next); + cur.next = head; + return cur; +} +``` +

diff --git a/problems/0028.实现strStr.md b/problems/0028.实现strStr.md index 629ff014..bf4ad600 100644 --- a/problems/0028.实现strStr.md +++ b/problems/0028.实现strStr.md @@ -1358,6 +1358,72 @@ impl Solution { } ``` +>前缀表统一不减一 +```C# +public int StrStr(string haystack, string needle) +{ + if (string.IsNullOrEmpty(needle)) + return 0; + + if (needle.Length > haystack.Length || string.IsNullOrEmpty(haystack)) + return -1; + + return KMP(haystack, needle); +} + +public int KMP(string haystack, string needle) +{ + int[] next = GetNext(needle); + int i = 0, j = 0; + while (i < haystack.Length) + { + if (haystack[i] == needle[j]) + { + i++; + j++; + } + if (j == needle.Length) + return i-j; + else if (i < haystack.Length && haystack[i] != needle[j]) + if (j != 0) + { + j = next[j - 1]; + } + else + { + i++; + } + } + return -1; +} + +public int[] GetNext(string needle) +{ + int[] next = new int[needle.Length]; + next[0] = 0; + int i = 1, j = 0; + while (i < needle.Length) + { + if (needle[i] == needle[j]) + { + next[i++] = ++j; + } + else + { + if (j == 0) + { + next[i++] = 0; + } + else + { + j = next[j - 1]; + } + } + } + return next; +} +``` +

diff --git a/problems/0151.翻转字符串里的单词.md b/problems/0151.翻转字符串里的单词.md index 111c07e4..d15bb5f3 100644 --- a/problems/0151.翻转字符串里的单词.md +++ b/problems/0151.翻转字符串里的单词.md @@ -972,6 +972,13 @@ char * reverseWords(char * s){ } ``` +### C# +```C# LINQ高级方法 +public string ReverseWords(string s) { + return string.Join(' ', s.Trim().Split(' ',StringSplitOptions.RemoveEmptyEntries).Reverse()); +} +``` +

diff --git a/problems/0459.重复的子字符串.md b/problems/0459.重复的子字符串.md index 177c3878..3245d948 100644 --- a/problems/0459.重复的子字符串.md +++ b/problems/0459.重复的子字符串.md @@ -681,6 +681,32 @@ impl Solution { } } ``` +### C# +```C# +// 前缀表不减一 +public bool RepeatedSubstringPattern(string s) +{ + if (s.Length == 0) + return false; + int[] next = GetNext(s); + int len = s.Length; + if (next[len - 1] != 0 && len % (len - next[len - 1]) == 0) return true; + return false; +} +public int[] GetNext(string s) +{ + int[] next = Enumerable.Repeat(0, s.Length).ToArray(); + for (int i = 1, j = 0; i < s.Length; i++) + { + while (j > 0 && s[i] != s[j]) + j = next[j - 1]; + if (s[i] == s[j]) + j++; + next[i] = j; + } + return next; +} +```

diff --git a/problems/0707.设计链表.md b/problems/0707.设计链表.md index c27f0107..a08227d9 100644 --- a/problems/0707.设计链表.md +++ b/problems/0707.设计链表.md @@ -1485,6 +1485,77 @@ impl MyLinkedList { } ``` +### C# +```C# +class ListNode +{ + public int val; + public ListNode next; + public ListNode(int val) { this.val = val; } +} +public class MyLinkedList +{ + ListNode dummyHead; + int count; + + public MyLinkedList() + { + dummyHead = new ListNode(0); + count = 0; + } + + public int Get(int index) + { + if (index < 0 || count <= index) return -1; + ListNode current = dummyHead; + for (int i = 0; i <= index; i++) + { + current = current.next; + } + return current.val; + } + + public void AddAtHead(int val) + { + AddAtIndex(0, val); + } + + public void AddAtTail(int val) + { + AddAtIndex(count, val); + } + + public void AddAtIndex(int index, int val) + { + if (index > count) return; + index = Math.Max(0, index); + count++; + ListNode tmp1 = dummyHead; + for (int i = 0; i < index; i++) + { + tmp1 = tmp1.next; + } + ListNode tmp2 = new ListNode(val); + tmp2.next = tmp1.next; + tmp1.next = tmp2; + } + + public void DeleteAtIndex(int index) + { + + if (index >= count || index < 0) return; + var tmp1 = dummyHead; + for (int i = 0; i < index; i++) + { + tmp1 = tmp1.next; + } + tmp1.next = tmp1.next.next; + count--; + + } +} +``` +

diff --git a/problems/面试题02.07.链表相交.md b/problems/面试题02.07.链表相交.md index 5de9da5c..adeaa413 100644 --- a/problems/面试题02.07.链表相交.md +++ b/problems/面试题02.07.链表相交.md @@ -502,6 +502,20 @@ object Solution { } } ``` +### C# +```C# +public ListNode GetIntersectionNode(ListNode headA, ListNode headB) +{ + if (headA == null || headB == null) return null; + ListNode cur1 = headA, cur2 = headB; + while (cur1 != cur2) + { + cur1 = cur1 == null ? headB : cur1.next; + cur2 = cur2 == null ? headA : cur2.next; + } + return cur1; +} +```