Assume the existence of an N x M matrix of characters, you are requested to find the character that is most commonly used in the whole matrix. For example: Input: [ G A C E C F] [ B C F A A F] [ F A G B A D] [ F F G A C C] [ E E F A E D] [ C E F B G A] [ D A D C F D] [ D F A G D C] Output: The most common characters are: F and A a) Design an efficient algorithm with the lowest possible complexity to solve this problem, and explain why your algorithm is efficient. (10 marks) b) Analyze the complexity of your algorithm. (5 marks