fibonacci-secuence-recurrence.kt

/*
 * Copyright 2023 marlonlom
 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */

/**
 * Returns Fibonacci number for selected number, using recurrence relation formula.
 *  
 *  F_{0}=0, F_{1}=1,
 *  F_{n}=F_{n-1}+F_{n-2}}
 * for n > 1.
 * 
 * @author marlonlom 
 */
fun Int.fibonacci():Int {
    val x= mutableListOf<Int>()
    x.add(0)
    x.add(1)
    for(i in 2..this){
      x.add(x[i-1] + x[i-2])
    }
    return x.get(this)
}