# 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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