feat: add leetcode solutions: No.0709. To Lower Case 

feat: update leetcode solutions: No.0304. Range Sum Query 2D - Immutable 

feat: update leetcode solutions: No.0199. Binary Tree Right Side View 

feat: update leetcode solutions: No.0019. Remove Nth Node From End of… … List

feat: add solutions to leetcode problem: No.1047 

feat: update solutions to leetcode problem: No.0002 

fix: update sorting algorithms 

feat: add golang solution for leetcode 0097