摘要：
You are given a string s, and an array of pairs of indices in the string pairs where pairs[i] = [a, b] indicates 2 indices(0-indexed) of the string. Y 阅读全文
摘要：
Given the API rand7() that generates a uniform random integer in the range [1, 7], write a function rand10() that generates a uniform random integer i 阅读全文