Array/String:
- 1768. Merge Strings Alternately: use StringBuilder
- 1071. Greatest Common Divisor of Strings: if str1 and str2 can be divided, then
[math]\displaystyle{ str1 + str2 = str2 + str1 \gcd(a,b)=\gcd(b,a \bmod b) }[/math] just get the substring of gcd length
- 1431. Kids With the Greatest Number of Candies: find the max value first
- 605. Can Place Flowers: check neighbours
- 345. Reverse Vowels of a String: exchange local array
- 151. Reverse Words in a String: split and then concat/ reverse array
- 238. Product of Array Except Self: p = p_left * p_right