Stream merge: Difference between revisions
→{{header|Elixir}}
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Line 580:
}
</lang>
=={{header|D}}==
<lang D>import std.range.primitives;
import std.stdio;
// An output range for writing the elements of the example ranges
struct OutputWriter {
void put(E)(E e) if (!isInputRange!E) {
stdout.write(e);
}
}
void main() {
import std.range : only;
merge2(OutputWriter(), only(1,3,5,7), only(2,4,6,8));
writeln("\n---------------");
mergeN(OutputWriter(), only(1,4,7), only(2,5,8), only(3,6,9));
writeln("\n---------------");
mergeN(OutputWriter(), only(1,2,3));
}
/+ Write the smallest element from r1 and r2 until both ranges are empty +/
void merge2(IN,OUT)(OUT sink, IN r1, IN r2)
if (isInputRange!IN && isOutputRange!(OUT, ElementType!IN)) {
import std.algorithm : copy;
while (!r1.empty && !r2.empty) {
auto a = r1.front;
auto b = r2.front;
if (a<b) {
sink.put(a);
r1.popFront;
} else {
sink.put(b);
r2.popFront;
}
}
copy(r1, sink);
copy(r2, sink);
}
/+ Write the smallest element from the sources until all ranges are empty +/
void mergeN(OUT,IN)(OUT sink, IN[] source ...)
if (isInputRange!IN && isOutputRange!(OUT, ElementType!IN)) {
ElementType!IN value;
bool done, hasValue;
int idx;
do {
hasValue = false;
done = true;
idx = -1;
foreach(i,r; source) {
if (!r.empty) {
if (hasValue) {
if (r.front < value) {
value = r.front;
idx = i;
}
} else {
hasValue = true;
value = r.front;
idx = i;
}
}
}
if (idx > -1) {
sink.put(source[idx].front);
source[idx].popFront;
done = false;
}
} while (!done);
}</lang>
{{out}}
<pre>12345678
---------------
123456789
---------------
123</pre>
=={{header|Elixir}}==
| |||