geeksforgeeks: add fibonacci

Author: smoothprogrammer

geeksforgeeks/fibonacci/README.md

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+# Fibonacci
+
+Given a number n, find n-th Fibonacci Number.
+
+## Copyright Notice
+
+This problem is based on [content](https://www.geeksforgeeks.org/program-for-nth-fibonacci-number/)
+from [GeeksforGeeks](https://www.geeksforgeeks.org)
+written by GeeksforGeeks
+and subject to [GeeksforGeeks copyright](https://www.geeksforgeeks.org/legal/copyright-information/).
+The original content from GeeksforGeeks and any modifications made here are attributed to GeeksforGeeks contributors,
+and this work is shared under [CC BY-SA 4.0](../LICENSE).

geeksforgeeks/fibonacci/solution.go

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+package fibonacci
+
+func Solution(n int) int {
+	memoization := make([]int, n+1)
+	return fib(n, memoization)
+}
+
+func fib(n int, memoization []int) int {
+	if n <= 1 {
+		return n
+	}
+
+	if number := memoization[n]; number != 0 {
+		return number
+	}
+
+	memoization[n] = fib(n-1, memoization) + fib(n-2, memoization)
+	return memoization[n]
+}

geeksforgeeks/fibonacci/solution_test.go

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+package fibonacci_test
+
+import (
+	"strconv"
+	"testing"
+
+	"github.com/minizilla/minmax/geeksforgeeks/fibonacci"
+	"github.com/minizilla/testr"
+)
+
+func TestFibonacci(t *testing.T) {
+	fib := []int{0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55}
+
+	for n, number := range fib {
+		t.Run(strconv.Itoa(n), func(t *testing.T) {
+			assert := testr.New(t)
+			out := fibonacci.Solution(n)
+			assert.Equal(out, number)
+		})
+	}
+}