Check necessary condition for condition for existence of full countOpsation
for i in range ( 1 , n ) : NEW_LINE INDENT for j in range ( 1 , n ) : NEW_LINE INDENT if ( A [ i ] [ j ] - A [ i ] [ 0 ] - A [ 0 ] [ j ] + A [ 0 ] [ 0 ] != 0 ) : NEW_LINE INDENT return - 1 ; NEW_LINE DEDENT DEDENT DEDENT