**Swap Kth Node Values - Amazon Top Interview Questions**

### Problem Statement :

You are given a singly linked list node and an integer k. Swap the value of the k-th (0-indexed) node from the end with the k-th node from the beginning. Constraints 1 ≤ n ≤ 100,000 where n is the number of nodes in node 0 ≤ k < n Example 1 Input node = [1, 2, 3, 4, 5, 6] k = 1 Output [1, 5, 3, 4, 2, 6] Explanation We swap 2 and 5. Example 2 Input node = [0, 6, 8, 2, 9] k = 2 Output [0, 6, 8, 2, 9] Explanation We swap 8 with 8.

### Solution :

` ````
Solution in C++ :
LLNode* solve(LLNode* node, int k) {
LLNode* dummy = new LLNode(-1, node);
auto begin = node, end = node, temp = node, prevbegin = dummy, prevend = dummy;
while (k--) {
prevbegin = begin;
begin = begin->next;
temp = temp->next;
}
while (temp->next) {
prevend = end;
temp = temp->next;
end = end->next;
}
prevbegin->next = end;
prevend->next = begin;
auto bnex = begin->next;
begin->next = end->next;
end->next = bnex;
return dummy->next;
}
```

` ````
Solution in Python :
class Solution:
def solve(self, node, k):
prev = node
curr = node
first = node
while curr.next != None:
curr = curr.next
if k > 0:
first = first.next
if k <= 0:
prev = prev.next
k -= 1
first.val, prev.val = prev.val, first.val
return node
```

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