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Count Duplicates in Array

by skibulk

JavaScript

console.clear();

var log = [];

for (var i = 0; i < 100; i++){
	log.push(Math.floor(Math.random()*1000000));
}

log.sort(function(a, b){
	return a - b;
});

function countDuplicates(arr){
	var count = 0;
  for(var i = 0; i < arr.length - 1; i++){
  	if(arr[i] == arr[i + 1]){
    	count++;
    }
  }
  return count;
}

console.log(log, countDuplicates(log));