Antonio Gulli's coding playground

Assume the stream of integers is appearing in array 'a'.
Initialize -
majority = a[0];
counter = 1;

As the number comes in (i=1 onwards) -
if a[i] == majority -> counter++;
else if counter == 0 -> majority = a[i];
else counter--;

At the end, if there is majority, it is saved in the variable majority.