go-lang-hacker-rank.go

# https://www.hackerrank.com/challenges/ctci-array-left-rotation/problem

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)	

// Complete the rotLeft function below.
func rotLeft(a []int32, d int32) []int32 {
	pos := int(d) % len(a)

	if pos == 0 {
		return a
	}

	newSlice := make([]int32, len(a), len(a))

	for i := 0; i < len(a); i++ {
		j := pos + i
		if j >= len(a) {
			j = j - len(a)
		}

		newSlice[i] = a[j]
	}

	return newSlice
}

func main() {
	reader := bufio.NewReaderSize(os.Stdin, 1024*1024)

	stdout, err := os.Create(os.Getenv("OUTPUT_PATH"))
	checkError(err)

	defer stdout.Close()

	writer := bufio.NewWriterSize(stdout, 1024*1024)

	nd := strings.Split(readLine(reader), " ")

	nTemp, err := strconv.ParseInt(nd[0], 10, 64)
	checkError(err)
	n := int32(nTemp)

	dTemp, err := strconv.ParseInt(nd[1], 10, 64)
	checkError(err)
	d := int32(dTemp)

	aTemp := strings.Split(readLine(reader), " ")

	var a []int32

	for i := 0; i < int(n); i++ {
		aItemTemp, err := strconv.ParseInt(aTemp[i], 10, 64)
		checkError(err)
		aItem := int32(aItemTemp)
		a = append(a, aItem)
	}

	result := rotLeft(a, d)

	for i, resultItem := range result {
		fmt.Fprintf(writer, "%d", resultItem)

		if i != len(result)-1 {
			fmt.Fprintf(writer, " ")
		}
	}

	fmt.Fprintf(writer, "\n")

	writer.Flush()
}

func readLine(reader *bufio.Reader) string {
	str, _, err := reader.ReadLine()
	if err == io.EOF {
		return ""
	}

	return strings.TrimRight(string(str), "\r\n")
}

func checkError(err error) {
	if err != nil {
		panic(err)
	}
}