https://saobear.online/Article/leetcode-%EF%BC%88643-%E5%AD%90%E6%95%B0%E7%BB%84%E6%9C%80%E5%A4%A7%E5%B9%B3%E5%9D%87%E6%95%B0-i%EF%BC%89/ 643.子数组最大平均数 I
https://saobear.online/Article/leetcode-%EF%BC%88643-%E5%AD%90%E6%95%B0%E7%BB%84%E6%9C%80%E5%A4%A7%E5%B9%B3%E5%9D%87%E6%95%B0-i%EF%BC%89/
643.子数组最大平均数 I