Matrix Ladder

Joaozinho is learning about arrays. Today he learned how to make arrays on the ladder shape, and exercising. To help him, you should write a program that determines if the result of it really is in the correct format.

A matrix is ladder shaped when, for each line, the following conditions are met:

• If the line has only zeros, then all rows below it also only have zeros.
• Otherwise, X is nonzero element of the leftmost line; Then, for all the lines below the line X, all elements in the columns left of X and X are zero.