2019B轮的统计数据
三道题：
1. Building Palindromes https://codingcompetitions.withgoogle.com/kickstart/round/0000000000050eda/0000000000119866
2. Energy Stones https://codingcompetitions.withgoogle.com/kickstart/round/0000000000050eda/00000000001198c3
3. Diverse Subarray https://codingcompetitions.withgoogle.com/kickstart/round/0000000000050eda/00000000001198c1
具体题目学习另开三篇文章
