Submission #1125458

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Source Code Expand

package main
import (
    "os"
    "bufio"
    "fmt"
    "strconv"
    "math"
    "sort"
)

var sc = bufio.NewScanner(os.Stdin)

func nextLine() string {
    sc.Scan()
    return sc.Text()
}

func main() {
    line := nextLine()
    n, _ := strconv.Atoi(line)
    ans := 0.
    r := make([]int, n) // int32だとエラー
    for i := 0; i < n; i += 1 {
        line = nextLine()
        r[i], _ = strconv.Atoi(line)
    }
    //sort.Ints(r) // 昇順でのsort
    sort.Sort(sort.Reverse(sort.IntSlice(r)))
    for i := 0; i < n; i += 1 {
        ans += math.Pow(-1, float64(i)) * math.Pi * math.Pow(float64(r[i]), 2)
    }

    fmt.Println(ans)
}

Submission Info

Judge Result