codingame - Temperature

main.go

package main

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

func main() {
    scanner := bufio.NewScanner(os.Stdin)

    // N: the number of temperatures to analyse
    var N int
    scanner.Scan()
    fmt.Sscan(scanner.Text(),&N)
    fmt.Fprintln(os.Stderr, "number of values: " + strconv.Itoa(N))

    scanner.Split(bufio.ScanWords)
    var values []int
    var result int

    for scanner.Scan() {
        // the N temperatures expressed as integers ranging from -273 to 5526
        x, err := strconv.Atoi(scanner.Text())
        if err != nil {
            panic(err)
        }
        values = append(values, x)
    }
    
    result = closest(values, 0)

    // fmt.Fprintln(os.Stderr, "sum: " + strconv.Itoa(sum))

    fmt.Println(result)// Write answer to stdout
}

func closest(values []int, median int) int {
	var result int
	var curr int
	for i := 0; i < len(values); i++ {
        fmt.Fprintln(os.Stderr, "=============================")

		fmt.Fprintln(os.Stderr, "pos: " + strconv.Itoa(i))
		curr = values[i]
		fmt.Fprintln(os.Stderr, "curr: " + strconv.Itoa(curr))
		fmt.Fprintln(os.Stderr, "rest: " + strconv.Itoa(result))
		if i == 0 {
			result = curr
		} else {
			if abs(curr) < abs(result){
				result = curr
			} else if abs(curr) == abs(result) {
			    if curr != result {
			        result = abs(result)
			    } else {
				    result = result
			    }
			} else {
				result = result
			}
		}
	}
	return result
}

// from src/image/png/paeth.go
// intSize is either 32 or 64.
const intSize = 32 << (^uint(0) >> 63)

func abs(x int) int {
	// m := -1 if x < 0. m := 0 otherwise.
	m := x >> (intSize - 1)

	// In two's complement representation, the negative number
	// of any number (except the smallest one) can be computed
	// by flipping all the bits and add 1. This is faster than
	// code with a branch.
	// See Hacker's Delight, section 2-4.
	return (x ^ m) - m
}