Problem:
Score : 200 points

Problem Statement

Given N integers A_1, ..., A_N, compute A_1 \times ... \times A_N.

However, if the result exceeds 10^{18}, print -1 instead.

Constraints

2 \leq N \leq 10^5

0 \leq A_i \leq 10^{18}

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 ... A_N

Output

Print the value A_1 \times ... \times A_N as an integer, or -1 if the value exceeds 10^{18}.

Sample Input 1

2
1000000000 1000000000

Sample Output 1

1000000000000000000

We have 1000000000 \times 1000000000 = 1000000000000000000.

Sample Input 2

3
101 9901 999999000001

Sample Output 2

-1

We have 101 \times 9901 \times 999999000001 = 1000000000000000001, which exceeds 10^{18}, so we should print -1 instead.

Sample Input 3

31
4 1 5 9 2 6 5 3 5 8 9 7 9 3 2 3 8 4 6 2 6 4 3 3 8 3 2 7 9 5 0

Sample Output 3

0

Solution in Go (1.14.1) (judge verdict: Wrong Answer)

package main

import (
	"bufio"
	"fmt"
	"log"
	"math/big"
	"os"
	"strconv"
)

func main() {
	n := readInt64()
	a := readInt64Slice(n)

	answer := big.NewInt(1)
	max := big.NewInt(10).Exp(big.NewInt(10), big.NewInt(18), nil)
	for _, v := range a {
		if v == 0 {
			fmt.Println(0)
			return
		}
		answer.Mul(answer, big.NewInt(v))
		if answer.Cmp(max) > 0 {
			fmt.Println(-1)
			return
		}
	}
	if answer.Cmp(max) > 0 {
		fmt.Println(-1)
		return
	}
	fmt.Println(answer)
}

var (
	scanner *bufio.Scanner
)

func init() {
	scanner = bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
}

func readInt64() int64 {
	var t string

	if scanner.Scan() {
		t = scanner.Text()
	}

	n, err := strconv.ParseInt(t, 10, 64)
	if err != nil {
		log.Fatal(err)
	}

	return n

}

func readInt64Slice(n int64) []int64 {
	s := make([]int64, n)
	var t string

	for i := 0; i < int(n); i++ {
		if scanner.Scan() {
			t = scanner.Text()
		}

		num, err := strconv.ParseInt(t, 10, 64)
		if err != nil {
			log.Fatal(err)
		}
		s[i] = num
	}

	return s
}