Determine the positions of each letter in a given 2D character array. Then output the positions of each letter in lexicographical order. For each letter, output its positions from left-top to right-bottom.
First, you will get an integer N, N <= 2000, meaning you will get an N*N 2D character array. Then, you will get N lines of input and N characters in each line.
Please output each position using the format (x,y), and then add a space between two positions. Remember to add ‘\n’ at the end of the outcome of every letter.