'ZigZag Conversion', string add solution, compare with the 'array append solution', performance is nearly same.
'ZigZag Conversion', string add solution, compare with the 'array append solution', performance is nearly same.

leonard-sxy/practice-and-accumulation,leonard-sxy/practice-and-accumulation,leonard-sxy/practice-and-accumulation,leonard-sxy/practice-and-accumulation,leonard-sxy/practice-and-accumulation