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Idiom #352 Parallelize 3 computations

Execute the functions f1, f2, f3 concurrently, and assign their respective return values to a1, a2, a3.

import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
List<Future<T>> a;
try (ExecutorService executorService = Executors.newFixedThreadPool(3)) {
    a = executorService.invokeAll(List.of(f1, f2, f3));
}

T a1 = a.get(0).get();
T a2 = a.get(1).get();
T a3 = a.get(2).get();
import "sync"
var wg sync.WaitGroup
wg.Add(3)
go func() {
	a1 = f1()
	wg.Done()
}()
go func() {
	a2 = f2()
	wg.Done()
}()
go func() {
	a3 = f3()
	wg.Done()
}()
wg.Wait()
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List<Future<T>> a;
try (ExecutorService executorService = Executors.newFixedThreadPool(3)) {
    a = executorService.invokeAll(List.of(f1, f2, f3));
}

T a1 = a.get(0).get();
T a2 = a.get(1).get();
T a3 = a.get(2).get();
var wg sync.WaitGroup
wg.Add(3)
go func() {
	a1 = f1()
	wg.Done()
}()
go func() {
	a2 = f2()
	wg.Done()
}()
go func() {
	a3 = f3()
	wg.Done()
}()
wg.Wait()