Given an array w
of positive integers, where w[i]
describes the
weight of index i
, write a function pickIndex
which
randomly picks an index in proportion to its weight.
Note:
1 <= w.length <= 10000
1 <= w[i] <= 10^5
pickIndex
will be called at most 10000
times.Example 1:
Input: ["Solution","pickIndex"] [[[1]],[]] Output: [null,0]
Example 2:
Input: ["Solution","pickIndex","pickIndex","pickIndex","pickIndex","pickIndex"] [[[1,3]],[],[],[],[],[]] Output: [null,0,1,1,1,0]