Comb

Generates every possible combination of r elements of the given sequence, or array indices from zero to N, depending on which c'tor is called. Uses an input range interface.

Note: The buffer that is returned by front is recycled across iterations. To duplicate it instead, use map!"a.dup" or map!"a.idup".

struct Comb (

) {

this(uint n, uint r);

this(T[] array, uint r);

const(T)[] front [@property getter];

void popFront();

bool empty [@property getter];

size_t length [@property getter];

typeof(this) save [@property getter];

}

Constructors

this this(uint n, uint r): Ctor to generate all possible combinations of array indices for a length r array. This is a special-case optimization and is faster than simply using the other ctor to generate all length r combinations from seq(0, length).
this this(T[] array, uint r): General ctor. array is a sequence from which to generate the * combinations. r is the length of the combinations to be generated.

Members

Functions

popFront void popFront(): Advances to the next combination. The array returned by front will be overwritten with the new results.

Properties

empty bool empty [@property getter]
front const(T)[] front [@property getter]: Gets the current combination.
length size_t length [@property getter]
save typeof(this) save [@property getter]

Only supports iterating over up to size_t.max combinations. This was a conscious tradeoff to allow this range to have a length of type size_t, since iterating over such huge combination spaces would be insanely slow anyhow.

Examples

1 auto comb1 = map!"a.dup"(Comb!(uint)(5, 2));
2 uint[][] vals;
3 foreach(c; comb1) {
4     vals ~= c;
5 }
6 auto sorted = sort(vals);
7 assert(sorted.canFind([0u,1]));
8 assert(sorted.canFind([0u,2]));
9 assert(sorted.canFind([0u,3]));
10 assert(sorted.canFind([0u,4]));
11 assert(sorted.canFind([1u,2]));
12 assert(sorted.canFind([1u,3]));
13 assert(sorted.canFind([1u,4]));
14 assert(sorted.canFind([2u,3]));
15 assert(sorted.canFind([2u,4]));
16 assert(sorted.canFind([3u,4]));
17 assert(sorted.length == 10);

Comb

Constructors

Members

Functions

Properties

Bugs

Examples

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