add code in the function of 2 questions to give the right output using PHP or any language.

I have 2 questions in which you will add code in its function. its my online test by hackerrank. my screenshots are in php language but you can do it on any language when i am giving test. you will be on skype or team viewer on test time. It will take your 15 - 20 minutes. I have done both the questions but output is not correct i dont know why. questions should be done correctly 100%. Each question has marks 50 and if you don't give the correct answer then it will give me 0 marks. questions are attached.... 1) triangle or not (3 pics of it sequence wise) 2) merge strings (3 pics of it sequence wise)