Merge 98999af into 0e7f631

README.md

@@ -411,4 +411,5 @@ problems from
 * [Day 412](https://github.com/vaskoz/dailycodingproblem-go/issues/832)
 * [Day 413](https://github.com/vaskoz/dailycodingproblem-go/issues/834)
 * [Day 414](https://github.com/vaskoz/dailycodingproblem-go/issues/836)
+* [Day 415](https://github.com/vaskoz/dailycodingproblem-go/issues/838)
 

day415/problem.go

@@ -0,0 +1,28 @@
+package day415
+
+// MaxProfitWithFee returns the maximum possible profit
+// by making transactions where each one has a fee.
+// A backtracking algorithm that tries all profitable paths
+// looking for the most profitable.
+func MaxProfitWithFee(prices []int, fee int) int {
+	if len(prices) < 2 {
+		return 0
+	}
+
+	buy := prices[0]
+
+	var maxProfit int
+
+	for i := 1; i < len(prices); i++ {
+		if prices[i] > buy+fee {
+			thisTradeProfit := prices[i] - buy - fee
+			totalProfit := thisTradeProfit + MaxProfitWithFee(prices[i+1:], fee)
+
+			if totalProfit > maxProfit {
+				maxProfit = totalProfit
+			}
+		}
+	}
+
+	return maxProfit
+}

day415/problem_test.go

@@ -0,0 +1,33 @@
+package day415
+
+import (
+	"reflect"
+	"testing"
+)
+
+// nolint
+var testcases = []struct {
+	prices    []int
+	fee       int
+	maxProfit int
+}{
+	{[]int{1, 3, 2, 8, 4, 10}, 2, 9},
+}
+
+func TestMaxProfitWithFee(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range testcases {
+		if result := MaxProfitWithFee(tc.prices, tc.fee); !reflect.DeepEqual(tc.maxProfit, result) {
+			t.Errorf("Expected %v, got %v", tc.maxProfit, result)
+		}
+	}
+}
+
+func BenchmarkMaxProfitWithFee(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range testcases {
+			MaxProfitWithFee(tc.prices, tc.fee)
+		}
+	}
+}