question: public static int [ ] [ ] deep_copy ( int M [ ] [ ] ) { int [ ] [ ] C = new int [ M . length ] [ ] ; for ( int i = 0 ; i < C . length ; i ++ ) { C [ i ] = Arrays . copyOf ( M [ i ] , M [ i ] . length ) ; } return C ; }
target:  Deep Copy - Make a deep copy of M[][].