// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
    }
}

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)
}

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
const values = new Array(A.length).fill(false)
  for (let i in A) {
    if (A[i] <= 0 || A[i] > A.length) {
      return 0
    }
    if (values[A[i] - 1] === true) {
      return 0
    }
    values[A[i] - 1] = true
  }
  return 1
}

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
  const values = new Array(A.length).fill(false)
  for (let i in A) {
    if (A[i] <= 0 || A[i] > A.length) {
      return 0
    }
    if (values[A[i] - 1] === true) {
      return 0
    }
    values[A[i] - 1] = true
  }
  return 1
}

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
  const values = new Array(A.length).fill(false)
  for (let i in A) {
    if (A[i] <= 0 || A[i] > A.length) {
      return 0
    }
    if (values[A[i] - 1] === true) {
      return 0
    }
    values[A[i] - 1] = true
  }
  return 1
}

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
  const values = new Array(A.length).fill(false)
  for (let i in A) {
    if (A[i] <= 0 || A[i] > A.length) {
      return 0
    }
    if (values[A[i] - 1] === true) {
      return 0
    }
    values[A[i] - 1] = true
  }
  return 1
}