# Algorithm for Median Review problem, with linear expected time via

# pairPartition$\_$Random.

# pairs is an array of pairs of $($score$,$ weight$).$

# It will be useful for you to implement the function as a SELECT variant:

# given array of pairs p$[$l:r$],$ and weight w$,$ find the score s$\_$i such that

# sum of weights of pairs $($s$\_$j$,$w$\_$j$)$ with s$\_$j