Time: 743 ms (7.46%), Space: 180.2 MB (16.39%) - LeetHub

1721-swapping-nodes-in-a-linked-list/1721-swapping-nodes-in-a-linked-list.cpp

@@ -0,0 +1,38 @@
+/**
+ * Definition for singly-linked list.
+ * 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) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode* swapNodes(ListNode* head, int k) {
+        ListNode* temp=head;
+        int cnt=0;
+        while(temp)
+        {
+            temp=temp->next;
+            cnt++;
+        }
+        cnt=cnt-k+1;
+        ListNode* chk=head;
+        ListNode* first;
+        ListNode* last;
+        int t=1;
+        while(chk)
+        {
+            if(t==k)first=chk;
+            if(t==cnt)last=chk;
+            t++;
+            chk=chk->next;    
+        }
+        int flag=first->val;
+        first->val=last->val;
+        last->val=flag;
+        return head;
+    }
+};