void main() {}
		import std.stdio; import std.string; import std.conv;
		import std.algorithm; import std.range; import std.array;
	unittest {
int[] a = ...;
static bool greater(int a, int b)
{
    return a > b;
}
sort!(greater)(a);  // predicate as alias
sort!("a > b")(a);  // predicate as string
                    // (no ambiguity with array name)
sort(a);            // no predicate, "a < b" is implicit

}
unittest {
int[] arr1 = [ 1, 2, 3, 4 ];
int[] arr2 = [ 5, 6 ];
auto squares = map!("a * a")(chain(arr1, arr2));
assert(equal(squares, [ 1, 4, 9, 16, 25, 36 ]));

}
unittest {
auto arr1 = [ 1, 2, 3, 4 ];
foreach (e; map!("a + a", "a * a")(arr1))
{
    writeln(e[0], " ", e[1]);
}

}
unittest {
alias map!(to!string) stringize;
assert(equal(stringize([ 1, 2, 3, 4 ]), [ "1", "2", "3", "4" ]));

}
unittest {
int[] arr = [ 1, 2, 3, 4, 5 ];
// Sum all elements
auto sum = reduce!("a + b")(0, arr);
assert(sum == 15);

// Compute the maximum of all elements
auto largest = reduce!(max)(arr);
assert(largest == 5);

// Compute the number of odd elements
auto odds = reduce!("a + (b & 1)")(0, arr);
assert(odds == 3);

// Compute the sum of squares
auto ssquares = reduce!("a + b * b")(0, arr);
assert(ssquares == 55);

// Chain multiple ranges into seed
int[] a = [ 3, 4 ];
int[] b = [ 100 ];
auto r = reduce!("a + b")(chain(a, b));
assert(r == 107);

// Mixing convertible types is fair game, too
double[] c = [ 2.5, 3.0 ];
auto r1 = reduce!("a + b")(chain(a, b, c));
assert(r1 == 112.5);

}
unittest {
double[] a = [ 3.0, 4, 7, 11, 3, 2, 5 ];
// Compute minimum and maximum in one pass
auto r = reduce!(min, max)(a);
// The type of r is Tuple!(double, double)
assert(r[0] == 2);  // minimum
assert(r[1] == 11); // maximum

// Compute sum and sum of squares in one pass
r = reduce!("a + b", "a + b * b")(tuple(0.0, 0.0), a);
assert(r[0] == 35);  // sum
assert(r[1] == 233); // sum of squares
// Compute average and standard deviation from the above
auto avg = r[0] / a.length;
auto stdev = sqrt(r[1] / a.length - avg * avg);

}
unittest {
int[] a = [ 1, 2, 3, 4 ];
fill(a, 5);
assert(a == [ 5, 5, 5, 5 ]);

}
unittest {
int[] a = [ 1, 2, 3, 4, 5 ];
int[] b = [ 8, 9 ];
fill(a, b);
assert(a == [ 8, 9, 8, 9, 8 ]);

}
unittest {
struct S { ... }
S[] s = (cast(S*) malloc(5 * S.sizeof))[0 .. 5];
uninitializedFill(s, 42);
assert(s == [ 42, 42, 42, 42, 42 ]);

}
unittest {
struct S { ... }
S[] s = (cast(S*) malloc(5 * S.sizeof))[0 .. 5];
initialize(s);
assert(s == [ 0, 0, 0, 0, 0 ]);

}
unittest {
int[] arr = [ 1, 2, 3, 4, 5 ];
// Sum all elements
auto small = filter!("a < 3")(arr);
assert(small == [ 1, 2 ]);
// In combination with chain() to span multiple ranges
int[] a = [ 3, -2, 400 ];
int[] b = [ 100, -101, 102 ];
auto r = filter!("a > 0")(chain(a, b));
assert(equal(r, [ 3, 400, 100, 102 ]));
// Mixing convertible types is fair game, too
double[] c = [ 2.5, 3.0 ];
auto r1 = filter!("cast(int) a != a")(chain(c, a, b));
assert(r1 == [ 2.5 ]);

}
unittest {
assert(equal(splitter("hello  world", ' ') == [ "hello", "", "world" ]));
int[] a = [ 1, 2, 0, 0, 3, 0, 4, 5, 0 ];
int[][] w = [ [1, 2], [], [3], [4, 5] ];
assert(equal(splitter(a, 0), w));
a = null;
assert(equal(splitter(a, 0), [ (int[]).init ]));
a = [ 0 ];
assert(equal(splitter(a, 0), [ (int[]).init, (int[]).init ]));
a = [ 0, 1 ];
assert(equal(splitter(a, 0), [ [], [1] ]));

}
unittest {
int[] arr = [ 1, 2, 2, 2, 2, 3, 4, 4, 4, 5 ];
assert(equal(uniq(arr), [ 1, 2, 3, 4, 5 ][]));

}
unittest {
int[] arr = [ 1, 2, 2, 2, 2, 3, 4, 4, 4, 5 ];
assert(equal(group(arr), [ tuple(1, 1u), tuple(2, 4u), tuple(3, 1u),
    tuple(4, 3u), tuple(5, 1u) ][]));

}
unittest {
assert(find("hello, world", ',') == ", world");
assert(find([1, 2, 3, 5], 4) == []);
assert(find(SList!int(1, 2, 3, 4, 5)[], 4) == SList!int(4, 5)[]);
assert(find!"a > b"([1, 2, 3, 5], 2) == [3, 5]);

auto a = [ 1, 2, 3 ];
assert(find(a, 5).empty);       // not found
assert(!find(a, 2).empty);      // found

// Case-insensitive find of a string
string[] s = [ "Hello", "world", "!" ];
assert(!find!("tolower(a) == b")(s, "hello").empty);

}
unittest {
assert(find("hello, world", "World").empty);
assert(find("hello, world", "wo") == "world");
assert(find([1, 2, 3, 4], SList!(2, 3)[]) == [2, 3, 4]);

}
unittest {
int[] a = [ 1, 4, 2, 3 ];
assert(find(a, 4) == [ 4, 2, 3 ]);
assert(find(a, [ 1, 4 ]) == [ 1, 4, 2, 3 ]);
assert(find(a, [ 1, 3 ], 4) == tuple([ 4, 2, 3 ], 2));
// Mixed types allowed if comparable
assert(find(a, 5, [ 1.2, 3.5 ], 2.0, [ 1 ]) == tuple([ 2, 3 ], 3));

}
unittest {
auto arr = [ 1, 2, 3, 4, 1 ];
assert(find!("a > 2")(arr) == [ 3, 4, 1 ]);

// with predicate alias
bool pred(int x) { return x + 1 > 1.5; }
assert(find!(pred)(arr) == arr);

}
unittest {
int[] a = [ 1, 2, 4, 7, 7, 2, 4, 7, 3, 5];
assert(equal(a.until(7), [1, 2, 4][]));
assert(equal(a.until(7, OpenRight.no), [1, 2, 4, 7][]));

}
unittest {
assert(startsWith("abc", ""));
assert(startsWith("abc", "a"));
assert(!startsWith("abc", "b"));
assert(startsWith("abc", 'a', "b") == 1);
assert(startsWith("abc", "b", "a") == 2);
assert(startsWith("abc", "a", "a") == 1);
assert(startsWith("abc", "x", "a", "b") == 2);
assert(startsWith("abc", "x", "aa", "ab") == 3);
assert(startsWith("abc", "x", "aaa", "sab") == 0);
assert(startsWith("abc", "x", "aaa", "a", "sab") == 3);

}
unittest {
assert(endsWith("abc", ""));
assert(!endsWith("abc", "b"));
assert(endsWith("abc", "a", 'c') == 2);
assert(endsWith("abc", "c", "a") == 1);
assert(endsWith("abc", "c", "c") == 1);
assert(endsWith("abc", "x", "c", "b") == 2);
assert(endsWith("abc", "x", "aa", "bc") == 3);
assert(endsWith("abc", "x", "aaa", "sab") == 0);
assert(endsWith("abc", "x", "aaa", 'c', "sab") == 3);

}
unittest {
assert(endsWith("abc", 'x', 'c', 'a') == 2);

}
unittest {
int[] a = [ 11, 10, 10, 9, 8, 8, 7, 8, 9 ];
auto r = findAdjacent(a);
assert(r == [ 10, 10, 9, 8, 8, 7, 8, 9 ]);
p = findAdjacent!("a < b")(a);
assert(p == [ 7, 8, 9 ]);

}
unittest {
int[] a = [ -1, 0, 1, 2, 3, 4, 5 ];
int[] b = [ 3, 1, 2 ];
assert(findAmong(a, b) == a[2 .. $]);

}
unittest {
int[] a = [ 1, 2, 4, 3, 2, 5, 3, 2, 4 ];
assert(count(a, 2) == 3);
assert(count!("a > b")(a, 2) == 5);

}
unittest {
int[] a = [ 1, 2, 4, 3, 2, 5, 3, 2, 4 ];
assert(count!("a > 1")(a) == 8);

}
unittest {
auto s = "1 + (2 * (3 + 1 / 2)";
assert(!balancedParens(s, '(', ')'));
s = "1 + (2 * (3 + 1) / 2)";
assert(balancedParens(s, '(', ')'));
s = "1 + (2 * (3 + 1) / 2)";
assert(!balancedParens(s, '(', ')', 1));
s = "1 + (2 * 3 + 1) / (2 - 5)";
assert(balancedParens(s, '(', ')', 1));

}
unittest {
int[] a = [ 1, 2, 4, 3 ];
assert(!equal(a, a[1..$]));
assert(equal(a, a));

// different types
double[] b = [ 1., 2, 4, 3];
assert(!equal(a, b[1..$]));
assert(equal(a, b));

// predicated: ensure that two vectors are approximately equal
double[] c = [ 1.005, 2, 4, 3];
assert(equal!(approxEqual)(b, c));

}
unittest {
int a = 5;
short b = 6;
double c = 2;
auto d = max(a, b);
assert(is(typeof(d) == int));
assert(d == 6);
auto e = min(a, b, c);
assert(is(typeof(e) == double));
assert(e == 2);

}
unittest {
int[] a = [ 2, 3, 4, 1, 2, 4, 1, 1, 2 ];
// Minimum is 1 and occurs 3 times
assert(minCount(a) == tuple(1, 3));
// Maximum is 4 and occurs 2 times
assert(minCount!("a > b")(a) == tuple(4, 2));

}
unittest {
int[] a = [ 2, 3, 4, 1, 2, 4, 1, 1, 2 ];
// Minimum is 1 and first occurs in position 3
assert(minPos(a) == [ 1, 2, 4, 1, 1, 2 ]);
// Maximum is 4 and first occurs in position 2
assert(minPos!("a > b")(a) == [ 4, 1, 2, 4, 1, 1, 2 ]);

}
unittest {
int[]    x = [ 1,  5, 2, 7,   4, 3 ];
double[] y = [ 1., 5, 2, 7.3, 4, 8 ];
auto m = mismatch(x, y);
assert(m[0] == x[3 .. $]);
assert(m[1] == y[3 .. $]);

}
unittest {
assert(levenshteinDistance("cat", "rat") == 1);
assert(levenshteinDistance("parks", "spark") == 2);
assert(levenshteinDistance("kitten", "sitting") == 3);
// ignore case
assert(levenshteinDistance!("toupper(a) == toupper(b)")
    ("parks", "SPARK") == 2);

}
unittest {
string a = "Saturday", b = "Sunday";
auto p = levenshteinDistanceAndPath(a, b);
assert(p[0] == 3);
assert(equal(p[1], "nrrnsnnn"));

}
unittest {
int[] a = [ 1, 5 ];
int[] b = [ 9, 8 ];
int[] c = new int[a.length + b.length + 10];
auto d = copy(b, copy(a, c));
assert(c[0 .. a.length + b.length] == a ~ b);
assert(d.length == 10);

}
unittest {
float[] a = [ 1.0f, 5 ];
double[] b = new double[a.length];
auto d = copy(a, b);

}
unittest {
int[] a = [ 1, 5, 8, 9, 10, 1, 2, 0 ];
auto b = new int[a.length];
auto c = copy(filter!("(a & 1) == 1")(a), b);
assert(b[0 .. $ - c.length] == [ 1, 5, 9, 1 ]);

}
unittest {
int[] a = [ 100, 101, 102, 103 ];
int[] b = [ 0, 1, 2, 3 ];
auto c = swapRanges(a[1 .. 3], b[2 .. 4]);
assert(c[0].empty && c[1].empty);
assert(a == [ 100, 2, 3, 103 ]);
assert(b == [ 0, 1, 101, 102 ]);

}
unittest {
int[] arr = [ 1, 2, 3 ];
reverse(arr);
assert(arr == [ 3, 2, 1 ]);

}
unittest {
auto arr = [4, 5, 6, 7, 1, 2, 3];
bringToFront(arr[0 .. 4], arr[4 .. $]);
assert(arr == [ 1, 2, 3, 4, 5, 6, 7 ]);

}
unittest {
auto list = SList!(int)(4, 5, 6, 7, 1, 2, 3);
auto r1 = list[];
auto r2 = list[]; popFrontN(r2, 4);
assert(equal(r2, [ 1, 2, 3 ]));
bringToFront(r1, r2);
assert(equal(list[], [ 1, 2, 3, 4, 5, 6, 7 ]));

}
unittest {
auto list = SList!(int)(4, 5, 6, 7);
auto vec = [ 1, 2, 3 ];
bringToFront(list[], vec);
assert(equal(list[], [ 1, 2, 3, 4 ]));
assert(equal(vec, [ 5, 6, 7 ]));

}
unittest {
int[] a = [ 3, 5, 7, 8 ];
assert(remove(a, 1) == [ 3, 7, 8 ]);
assert(a == [ 3, 7, 8, 8 ]);

}
unittest {
int[] a = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
assert(remove(a, 1, 3, 5) ==
    [ 0, 2, 4, 6, 7, 8, 9, 10 ]);

}
unittest {
int[] a = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
assert(remove(a, 1, tuple(3, 5), 9) == [ 0, 2, 6, 7, 8, 10 ]);

}
unittest {
int[] a = [ 0, 1, 2, 3 ];
assert(remove!(SwapStrategy.unstable)(a, 1) == [ 0, 3, 2 ]);

}
unittest {
int[] a = [ 1, 2, 3, 2, 3, 4, 5, 2, 5, 6 ];
assert(a[0 .. $ - remove!("a == 2")(a).length] == [ 1, 3, 3, 4, 5, 5, 6 ]);

}
unittest {
auto Arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
auto arr = Arr.dup;
static bool even(int a) { return (a & 1) == 0; }
// Partition arr such that even numbers come first
auto r = partition!(even)(arr);
// Now arr is separated in evens and odds.
// Numbers may have become shuffled due to instability
assert(r == arr[5 .. $]);
assert(count!(even)(arr[0 .. 5]) == 5);
assert(find!(even)(r).empty);

// Can also specify the predicate as a string.
// Use 'a' as the predicate argument name
arr[] = Arr[];
r = partition!(q{(a & 1) == 0})(arr);
assert(r == arr[5 .. $]);

// Now for a stable partition:
arr[] = Arr[];
r = partition!(q{(a & 1) == 0}, SwapStrategy.stable)(arr);
// Now arr is [2 4 6 8 10 1 3 5 7 9], and r points to 1
assert(arr == [2, 4, 6, 8, 10, 1, 3, 5, 7, 9] && r == arr[5 .. $]);

// In case the predicate needs to hold its own state, use a delegate:
arr[] = Arr[];
int x = 3;
// Put stuff greater than 3 on the left
bool fun(int a) { return a > x; }
r = partition!(fun, SwapStrategy.semistable)(arr);
// Now arr is [4 5 6 7 8 9 10 2 3 1] and r points to 2
assert(arr == [4, 5, 6, 7, 8, 9, 10, 2, 3, 1] && r == arr[7 .. $]);

}
unittest {
int[] r = [ 1, 3, 5, 7, 8, 2, 4, ];
assert(isPartitioned!("a & 1")(r));

}
unittest {
int[] v = [ 25, 7, 9, 2, 0, 5, 21 ];
auto n = 4;
topN!(less)(v, n);
assert(v[n] == 9);
// Equivalent form:
topN!("a < b")(v, n);
assert(v[n] == 9);

}
unittest {
int[] array = [ 1, 2, 3, 4 ];
// sort in descending order
sort!("a > b")(array);
assert(array == [ 4, 3, 2, 1 ]);
// sort in ascending order
sort(array);
assert(array == [ 1, 2, 3, 4 ]);
// sort with a delegate
bool myComp(int x, int y) { return x > y; }
sort!(myComp)(array);
assert(array == [ 4, 3, 2, 1 ]);
// Showcase stable sorting
string[] words = [ "aBc", "a", "abc", "b", "ABC", "c" ];
sort!("toupper(a) < toupper(b)", SwapStrategy.stable)(words);
assert(words == [ "a", "aBc", "abc", "ABC", "b", "c" ]);

}
unittest {
uint hashFun(string) { ... expensive computation ... }
string[] array = ...;
// Sort strings by hash, slow
sort!("hashFun(a) < hashFun(b)")(array);
// Sort strings by hash, fast (only computes arr.length hashes):
schwartzSort!(hashFun, "a < b")(array);

}
unittest {
int[] a = [ 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 ];
partialSort(a, 5);
assert(a[0 .. 5] == [ 0, 1, 2, 3, 4 ]);

}
unittest {
int[] a = [ 1, 2, 3 ];
int[] b = [ 4, 0, 6, 5 ];
completeSort(assumeSorted(a), b);
assert(a == [ 0, 1, 2 ]);
assert(b == [ 3, 4, 5, 6 ]);

}
unittest {
int[] arr = [4, 3, 2, 1];
assert(!isSorted(arr));
sort(arr);
assert(isSorted(arr));
sort!("a > b")(arr);
assert(isSorted!("a > b")(arr));

}
unittest {
immutable(int[]) arr = [ 2, 3, 1, 5, 0 ];
// index using pointers
auto index1 = new immutable(int)*[arr.length];
makeIndex!("a < b")(arr, index1);
assert(isSorted!("*a < *b")(index1));
// index using offsets
auto index2 = new size_t[arr.length];
makeIndex!("a < b")(arr, index2);
assert(isSorted!
    ((size_t a, size_t b){ return arr[a] < arr[b];})
    (index2));

}
unittest {
int[] a = [ 10, 16, 2, 3, 1, 5, 0 ];
int[] b = new int[3];
topNCopy(a, b, true);
assert(b == [ 0, 1, 2 ]);

}
unittest {
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
int[] c = [ 10 ];
assert(setUnion(a, b).length == a.length + b.length);
assert(equal(setUnion(a, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9][]));
assert(equal(setUnion(a, c, b),
    [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9, 10][]));

}
unittest {
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
int[] c = [ 0, 1, 4, 5, 7, 8 ];
assert(equal(setIntersection(a, a), a));
assert(equal(setIntersection(a, b), [1, 2, 4, 7][]));
assert(equal(setIntersection(a, b, c), [1, 4, 7][]));

}
unittest {
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
assert(equal(setDifference(a, b), [5, 9][]));

}
unittest {
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
assert(equal(setSymmetricDifference(a, b), [0, 5, 8, 9][]));

}
unittest {
double[][] a =
[
    [ 1, 4, 7, 8 ],
    [ 1, 7 ],
    [ 1, 7, 8],
    [ 4 ],
    [ 7 ],
];
auto witness = [
    1, 1, 1, 4, 4, 7, 7, 7, 7, 8, 8
];
assert(equal(nWayUnion(a), witness[]));

}
unittest {
// Figure which number can be found in most arrays of the set of
// arrays below.
double[][] a =
[
    [ 1, 4, 7, 8 ],
    [ 1, 7 ],
    [ 1, 7, 8],
    [ 4 ],
    [ 7 ],
];
auto b = new Tuple!(double, uint)[1];
largestPartialIntersection(a, b);
// First member is the item, second is the occurrence count
assert(b[0] == tuple(7.0, 4u));

}
unittest {
// Figure which number can be found in most arrays of the set of
// arrays below, with specific per-element weights
double[][] a =
[
    [ 1, 4, 7, 8 ],
    [ 1, 7 ],
    [ 1, 7, 8],
    [ 4 ],
    [ 7 ],
];
auto b = new Tuple!(double, uint)[1];
double[double] weights = [ 1:1.2, 4:2.3, 7:1.1, 8:1.1 ];
largestPartialIntersectionWeighted(a, b, weights);
// First member is the item, second is the occurrence count
assert(b[0] == tuple(4.0, 2u));

}