Fibonacci in O(n) time O(1) space: public int fibonacci(int n) { if (n == 1) return 1 int prev = 0, cur = 1; for(int i = 2; i <= n; i++} { int tmp = prev; prev = cur; cur = prev + cur; } return cur; }

Balance Parenthesis public static String balanceParenthesis(String s) { StringBuilder str = new StringBuilder(s); int left = 0; for(int i = 0; i 0) { left--; } else { str.deleteCharAt(i--); } } } int right = 0; for(int i = str.length() - 1; i >= 0; i--) { if(str.charAt(i) == ')') { right++; } else if(str.charAt(i) == '('){ if(right > 0) right--; else { str.deleteCharAt(i); } } } return str.toString(); }

Hi can you specify some question that we asked during the on site interview ? What was asked to code in the demo?