Project Euler: First Ten solutions

Author: ddaniel27

project_euler/problem_1/problem1.go

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+/**
+ * Problem 1 - Multiples of 3 and 5
+ *
+ * @see {@link https://projecteuler.net/problem=1}
+ *
+ * If we list all the natural numbers below 10 that are multiples of 3 or 5,
+ * we get 3, 5, 6 and 9. The sum of these multiples is 23.
+ * Find the sum of all the multiples of 3 or 5 below 1000.
+ *
+ * @author ddaniel27
+ */
+package problem1
+
+func Problem1(n uint) uint {
+	sum := uint(0)
+
+	for i := uint(1); i < n; i++ {
+		if i%3 == 0 || i%5 == 0 {
+			sum += i
+		}
+	}
+
+	return sum
+}

project_euler/problem_1/problem1_test.go

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+package problem1
+
+import "testing"
+
+// Tests
+func TestProblem1_Func(t *testing.T) {
+	tests := []struct {
+		name      string
+		threshold uint
+		want      uint
+	}{
+		{
+			name:      "Testcase 1 - threshold 10",
+			threshold: 10,
+			want:      23,
+		},
+		{
+			name:      "Testcase 2 - threshold 100",
+			threshold: 100,
+			want:      2318,
+		},
+		{
+			name:      "Testcase 3 - threshold 1000",
+			threshold: 1000,
+			want:      233168,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			n := Problem1(tt.threshold)
+
+			if n != tt.want {
+				t.Errorf("Problem1() = %v, want %v", n, tt.want)
+			}
+		})
+	}
+}
+
+// Benchmarks
+func BenchmarkProblem1(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = Problem1(1000)
+	}
+}

project_euler/problem_10/problem10.go

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+/**
+* Problem 10 - Summation of primes
+* @see {@link https://projecteuler.net/problem=10}
+*
+* The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
+* Find the sum of all the primes below two million.
+*
+* @author ddaniel27
+ */
+package problem10
+
+import "github.com/TheAlgorithms/Go/math/prime"
+
+func Problem10(n int) uint {
+	sum := uint(0)
+	sieve := prime.SieveEratosthenes(n)
+
+	for _, v := range sieve {
+		sum += uint(v)
+	}
+
+	return sum
+}

project_euler/problem_10/problem10_test.go

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+package problem10
+
+import "testing"
+
+// Tests
+func TestProblem10_Func(t *testing.T) {
+	tests := []struct {
+		name  string
+		input int
+		want  uint
+	}{
+		{
+			name:  "Testcase 1 - input 10",
+			input: 10,
+			want:  17,
+		},
+		{
+			name:  "Testcase 2 - input 2000000",
+			input: 2000000,
+			want:  142913828922,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			n := Problem10(tt.input)
+
+			if n != tt.want {
+				t.Errorf("Problem10() = %v, want %v", n, tt.want)
+			}
+		})
+	}
+}
+
+// Benchmarks
+func BenchmarkProblem10(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = Problem10(2000000)
+	}
+}

project_euler/problem_2/problem2.go

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+/**
+* Problem 2 - Even Fibonacci numbers
+* @see {@link https://projecteuler.net/problem=2}
+*
+* Each new term in the Fibonacci sequence is generated by adding the previous two terms.
+* By starting with 1 and 2, the first 10 terms will be:
+*
+* 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
+*
+* By considering the terms in the Fibonacci sequence whose values do not exceed four million,
+* find the sum of the even-valued terms.
+*
+* @author ddaniel27
+ */
+package problem2
+
+func Problem2(n uint) uint {
+	sum := uint(0)
+	a, b := uint(1), uint(2)
+
+	for b < n {
+		if b%2 == 0 {
+			sum += b
+		}
+
+		a, b = b, a+b
+	}
+
+	return sum
+}

project_euler/problem_2/problem2_test.go

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+package problem2
+
+import "testing"
+
+// Tests
+func TestProblem2_Func(t *testing.T) {
+	tests := []struct {
+		name  string
+		input uint
+		want  uint
+	}{
+		{
+			name:  "Testcase 1 - input 10",
+			input: 10,
+			want:  10,
+		},
+		{
+			name:  "Testcase 2 - input 100",
+			input: 100,
+			want:  44,
+		},
+		{
+			name:  "Testcase 3 - input 4e6",
+			input: 4e6,
+			want:  4613732,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			n := Problem2(tt.input)
+
+			if n != tt.want {
+				t.Errorf("Problem2() = %v, want %v", n, tt.want)
+			}
+		})
+	}
+}
+
+// Benchmarks
+func BenchmarkProblem2(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = Problem2(4e6)
+	}
+}

project_euler/problem_3/problem3.go

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+/**
+* Problem 3 - Largest prime factor
+* @see {@link https://projecteuler.net/problem=3}
+*
+* The prime factors of 13195 are 5, 7, 13 and 29.
+* What is the largest prime factor of the number 600851475143 ?
+*
+* @author ddaniel27
+ */
+package problem3
+
+func Problem3(n uint) uint {
+	i := uint(2)
+
+	for n > 1 {
+		if n%i == 0 {
+			n /= i
+		} else {
+			i++
+		}
+	}
+
+	return i
+}

project_euler/problem_3/problem3_test.go

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+package problem3
+
+import "testing"
+
+// Tests
+func TestProblem3_Func(t *testing.T) {
+	tests := []struct {
+		name  string
+		input uint
+		want  uint
+	}{
+		{
+			name:  "Testcase 1 - input 13195",
+			input: 13195,
+			want:  29,
+		},
+		{
+			name:  "Testcase 2 - input 600851475143",
+			input: 600851475143,
+			want:  6857,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			n := Problem3(tt.input)
+
+			if n != tt.want {
+				t.Errorf("Problem3() = %v, want %v", n, tt.want)
+			}
+		})
+	}
+}
+
+// Benchmarks
+func BenchmarkProblem3(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = Problem3(600851475143)
+	}
+}

project_euler/problem_4/problem4.go

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+/**
+* Problem 4 - Largest palindrome product
+* @see {@link https://projecteuler.net/problem=4}
+*
+* A palindromic number reads the same both ways.
+* The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.
+* Find the largest palindrome made from the product of two 3-digit numbers.
+*
+* @author ddaniel27
+ */
+package problem4
+
+import (
+	"fmt"
+
+	"github.com/TheAlgorithms/Go/strings/palindrome"
+)
+
+func Problem4() uint {
+	max := uint(0)
+
+	for i := 999; i >= 100; i-- {
+		for j := 999; j >= 100; j-- {
+			n := uint(i * j)
+
+			if palindrome.IsPalindrome(fmt.Sprintf("%d", n)) && n > max {
+				max = n
+			}
+		}
+	}
+
+	return max
+}

project_euler/problem_4/problem4_test.go

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+package problem4
+
+import "testing"
+
+// Tests
+func TestProblem4_Func(t *testing.T) {
+	tests := []struct {
+		name string
+		want uint
+	}{
+		{
+			name: "Testcase 1",
+			want: 906609,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			n := Problem4()
+
+			if n != tt.want {
+				t.Errorf("Problem4() = %v, want %v", n, tt.want)
+			}
+		})
+	}
+}
+
+// Benchmarks
+func BenchmarkProblem4(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = Problem4()
+	}
+}