#269 · #1533 · Find the Index of the Large Integer(找出数组中的大整数下标)

This is an interactive problem. An array of n integers has one element strictly larger than all others. ArrayReader.compareSub(l1, r1, l2, r2) compares the sums of two equal-length subarrays, returning 1, 0 or -1. Return the index of the largest element. Constraints: 2 <= n <= 5 * 10^4; at most 20 calls to compareSub.