**ImmunitoAI Software Engineer Intern (6M)**\n\n**Problem 1**\n**Longest Plaindromic Substring**: https://leetcode.com/problems/longest-palindromic-substring/\n\n**Problem 2**\n**Math Challenge**: Similar to https://leetcode.com/problems/target-sum/, except the target was zero and an integer number was given instead of a vector. You had to create a string of all operators that you would use in between the digits of the numbers to get to zero. If it was not possible, return string "not possible".\n\nExamples:\n\n\tinput: 32452\n\toutput: --+-\n\tExplanantion: 3-2-4+5-2 = 0\n\t\n\tinput: 199\n\toutput: not possible\n\tExplanation: Any combination cannot produce 0.\n\t\n**Problem 3**\n**String Challenge**: Given input as worded numbers and "plus" and "minus" operators, evaluate the expression and return answer in string format. If value becomes negative, add "negative" to the start of the answer string.\n\nExamples:\n\n\tinput: onezeropluseightminustwothree\n\toutput: negativefive\n\tExplanantion: 10 + 8 - 23 = -5\n\n\tinput: foursixplussevennine\n\toutput: onetwofive\n\tExplanation: 46 + 79 = 125

ImmunitoAI Software Engineer Intern (6M)\n\nProblem 1\nLongest Plaindromic Substring: https://leetcode.com/problems/longest-palindromic-substring/\n\nProblem 2\