1.Given a string, find the first non-repeating character in it. For example, if the input string is “apple”, then output should be ‘a’ and if input string is “aabbcde”, then output should be ‘c’. 2.Find the number which occurs maximum time in array without using nested loop. 3.Given an expression string exp , write a program to examine whether the pairs and the orders of “{“,”}”,”(“,”)”,”[“,”]” are correct in exp. 4. Find the area of two intersecting rectangle given their (Length, Breadth, X coordinate, Y coordinate) 5. Given a string, find the length of the longest substring without repeating characters.