We select a specific number of winners in a raffle, where the likelihood of winning is different for each participant.

For each round, i.e., for each time selecting one winner, we do the following:

• The array of likelihoods of the participants in the round is scaled so that their sum equals 1. [2,3,4,1] => [0.2,0.3,0.4,0.1]
• Create an array that is a cumulative sum array, i.e., [0.2,0.3,0.4,0.1] => [0.2,0.5,0.9,1.0]
• Generate a random number between 0 and 1;
• Find the index where the item in the array is biggest among the items less than or equal to the random number.

We have used Mersenne Twister.

The 'weightedSelection' returns the array of winner with the inputs (seed, array of likelihoods of participants,number of winners).