August 26, 2024
P10 - Run-length encoding of a list.
Use the result of problem P09 to implement the so-called run-length encoding data compression method. Consecutive duplicates of elements are encoded as tuples (N, E) where N is the number of duplicates of the element E.
Example:
> encode("aaaabccaadeeee".toList())
[(4, a), (1, b), (2, c), (2, a), (1, d), (4, e)]kotlin
package org.kotlin99.lists
import com.natpryce.hamkrest.assertion.assertThat
import com.natpryce.hamkrest.equalTo
import org.junit.Test
fun <T> encode(list: List<T>): List<Pair<Int, T>> =
pack(list).map { Pair(it.size, it.first()) }
class P10Test {
@Test fun `run-length encoding of a list`() {
assertThat(encode("aaaabccaadeeee".toList()), equalTo(listOf(
Pair(4, 'a'), Pair(1, 'b'), Pair(2, 'c'), Pair(2, 'a'), Pair(1, 'd'), Pair(4, 'e')
)))
}
}
Be first to comment