Version 5.0 The LEDA User Manual

6.2 Two Dimensional Arrays ( array2 )
1. Definition
An instance A of the parameterized data type array2 is a mapping from a set of pairs
I = [a..b] × [c..d], called the index set of A, to the set of variables of data type E, called
the element type of A, for two fixed intervals of integers [a..b] and [c..d]. A(i, j) is called
the element at position (i, j).
#include < LEDA/core/array2.h >
2. Creation
array2 A(int a, int b, int c, int d);
array2 A(int n, int m);
creates an instance A of type array2 with index set [a..b]×[c..d].
creates an instance A of type array2 with index set [0..n − 1] ×
[0..m − 1].
3. Operations
E& A(int i, int j) returns A(i, j).
Precondition: a ≤ i ≤ b and c ≤ j ≤ d.
int A.low1( ) returns a.
int A.high1( ) returns b.
int A.low2( ) returns c.
int A.high2( ) returns d.
4. Implementation
Two dimensional arrays are implemented by C++vectors. All operations take time O(1),
the space requirement is O(I ∗ sizeof(E)).