pwc143 solution in go

5 files changed, 103 insertions, 0 deletions

diff --git a/challenge-143/pokgopun/README b/challenge-143/pokgopun/README
new file mode 100644
index 0000000000..33dfd303a4
--- /dev/null
+++ b/challenge-143/pokgopun/README
@@ -0,0 +1 @@
+Solution by PokGoPun
diff --git a/challenge-143/pokgopun/go/ch-1.go b/challenge-143/pokgopun/go/ch-1.go
new file mode 100644
index 0000000000..21a469bc60
--- /dev/null
+++ b/challenge-143/pokgopun/go/ch-1.go
@@ -0,0 +1,28 @@
+/*
+You are given a string, $s, containing mathematical expression.
+
+Write a script to print the result of the mathematical expression. To keep it simple, please only accept + - * ().
+*/
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/Knetic/govaluate"
+)
+
+func main() {
+	if len(os.Args) < 2 {
+		os.Args = append(os.Args, "10 + 20 - 5", "(10 + 20 - 5) * 2", "8 * .7 - (3 - 13.5)")
+	}
+	for _, v := range os.Args[1:] {
+		expression, err := govaluate.NewEvaluableExpression(v)
+		result, err := expression.Evaluate(nil)
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf("Input: s = %q\nOutput: %v\n\n", v, result)
+	}
+}
diff --git a/challenge-143/pokgopun/go/ch-2.go b/challenge-143/pokgopun/go/ch-2.go
new file mode 100644
index 0000000000..7b85518d74
--- /dev/null
+++ b/challenge-143/pokgopun/go/ch-2.go
@@ -0,0 +1,35 @@
+/*
+You are given a positive number, $n.
+
+Write a script to find out if the given number is Stealthy Number.
+
+A positive integer N is stealthy, if there exist positive integers a, b, c, d such that a * b = c * d = N and a + b = c + d + 1.
+*/
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+
+	"github.com/pokgopun/go/stealthy"
+)
+
+func main() {
+	var nums []uint
+	if len(os.Args) > 1 {
+		for _, v := range os.Args[1:] {
+			n, err := strconv.ParseUint(v, 10, 64)
+			if err != nil {
+				log.Fatal(err)
+			}
+			nums = append(nums, uint(n))
+		}
+	} else {
+		nums = []uint{36, 12, 6}
+	}
+	for _, v := range nums {
+		fmt.Printf("Input: n = %d\nOutput: %t\n\n", v, stealthy.IsStealthy(v))
+	}
+}
diff --git a/challenge-143/pokgopun/go/stealthy/stealthy.go b/challenge-143/pokgopun/go/stealthy/stealthy.go
new file mode 100644
index 0000000000..cce77dfd12
--- /dev/null
+++ b/challenge-143/pokgopun/go/stealthy/stealthy.go
@@ -0,0 +1,22 @@
+package stealthy
+
+import (
+	"math"
+)
+
+func IsStealthy(n uint) bool {
+	lim := uint(math.Floor(math.Sqrt(float64(n))))
+	prev := n + 1
+	var sum uint
+	for d := uint(2); d <= lim; d++ {
+		if n%d == 0 {
+			sum = d + n/d
+			//fmt.Println("n=", n, "prev=", prev, "sum=", sum)
+			if prev-sum == 1 {
+				return true
+			}
+			prev = sum
+		}
+	}
+	return false
+}
diff --git a/challenge-143/pokgopun/go/stealthy/stealthy_test.go b/challenge-143/pokgopun/go/stealthy/stealthy_test.go
new file mode 100644
index 0000000000..840bc71d0f
--- /dev/null
+++ b/challenge-143/pokgopun/go/stealthy/stealthy_test.go
@@ -0,0 +1,17 @@
+package stealthy
+
+import "testing"
+
+func TestIsStealthy(t *testing.T) {
+	m := map[uint]bool{
+		36: true,
+		12: true,
+		6:  false,
+	}
+	for n, ans := range m {
+		res := IsStealthy(n)
+		if res != ans {
+			t.Errorf("incorrect result for %d: expected %t, got %t", n, ans, res)
+		}
+	}
+}