JSFiddle - React, Tailwind, and code Playground

by henser

JavaScript

function ping(n, ar) {

var count = 1,
		total = 0;

ar.sort();

for (let i = 1; n >= i ;i++) {
  let val = ar[i-1];
  
  if (val == ar[i]) {
    count++;
    continue;
  }
  
  if (count > 1) {
    total += count % 2 == 0 ? count/2 : (count-1)/2;
    count = 1;
  }
  

}

return total;

}

console.log(ping(9, [1,1,2,3,1,3,3,3,3]));