Question

How to find the first 4-digit prime number where all digits are unique in Node.js

Answer 1

function isPrime(n) {
  if (n < 2) return false;
  if (n % 2 === 0) return n === 2;

  const limit = Math.floor(Math.sqrt(n));
  for (let i = 3; i <= limit; i += 2) {
    if (n % i === 0) return false;
  }
  
  return true;
}

function hasUniqueDigits(n) {
  const digits = String(n);
  const unique = new Set(digits);
  
  return unique.size === digits.length;
}

for (let num = 1000; num <= 9999; num++) {
  if (isPrime(num) && hasUniqueDigits(num)) {
    console.log(`First 4-digit prime with all unique digits: ${num}`);
    return; // stop after finding the first one
  }
}

console.log("No such number found.");



/*
run:
   
First 4-digit prime with all unique digits: 1039
   
*/

 

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