kth-last-node.js
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const assert = require('assert')
class Node {
constructor(value) {
this.value = value
}
}
class NodeBuilder {
add(value) {
if (this.first == null) {
this.first = this.last = new Node(value)
} else {
this.last.next = new Node(value)
this.last = this.last.next
}
return this
}
build() {
return this.first
}
}
Node.add = (value) => {
let builder = new NodeBuilder()
return builder.add(value)
}
const node = Node
.add('this')
.add('is')
.add('mason')
.build()
let lastNode = kthLastNode(node, 1);
assert(lastNode === 'mason', lastNode)
function kthLastNode(node, kth) {
let count = 0
let first = null
while (node != null) {
count += 1
if (first == null) {
first = node
} else {
if (count > kth) {
first = first.next
}
}
node = node.next
}
return first.value
}
JavaScript
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