kazuyamaa/multi-language-messages-01 huggingface dataset:
Task: Find words with alternating vowels and consonants
C: #include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_WORD_SIZE 80

bool is_vowel(char ch) {
    switch (ch) {
    case 'a': case 'A':
    case 'e': case 'E':
    case 'i': case 'I':
    case 'o': case 'O':
    case 'u': case 'U':
        return true;
    }
    return false;
}

bool alternating_vowels_and_consonants(const char* str, size_t len) {
    for (size_t i = 1; i < len; ++i) {
        if (is_vowel(str[i]) == is_vowel(str[i - 1]))
            return false;
    }
    return true;
}

int main(int argc, char** argv) {
    const char* filename = argc < 2 ? "unixdict.txt" : argv[1];
    FILE* fp = fopen(filename, "r");
    if (!fp) {
        perror(filename);
        return EXIT_FAILURE;
    }
    char line[MAX_WORD_SIZE];
    int n = 1;
    while (fgets(line, sizeof(line), fp)) {
        size_t len = strlen(line) - 1; 
        if (len > 9 && alternating_vowels_and_consonants(line, len))
            printf("%2d: %s", n++, line);
    }
    fclose(fp);
    return EXIT_SUCCESS;
}

C++: #include <cstdlib>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <string>

bool is_vowel(char ch) {
    switch (ch) {
    case 'a': case 'A':
    case 'e': case 'E':
    case 'i': case 'I':
    case 'o': case 'O':
    case 'u': case 'U':
        return true;
    }
    return false;
}

bool alternating_vowels_and_consonants(const std::string& str) {
    for (size_t i = 1, len = str.size(); i < len; ++i) {
        if (is_vowel(str[i]) == is_vowel(str[i - 1]))
            return false;
    }
    return true;
}

int main(int argc, char** argv) {
    const char* filename = argc < 2 ? "unixdict.txt" : argv[1];
    std::ifstream in(filename);
    if (!in) {
        std::cerr << "Cannot open file '" << filename << "'.\n";
        return EXIT_FAILURE;
    }
    std::string line;
    for (int n = 1; getline(in, line); ) {
        if (line.size() > 9 && alternating_vowels_and_consonants(line))
            std::cout << std::setw(2) << n++ << ": " << line << '\n';
    }
    return EXIT_SUCCESS;
}
Task: Find words with alternating vowels and consonants
C: #include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_WORD_SIZE 80

bool is_vowel(char ch) {
    switch (ch) {
    case 'a': case 'A':
    case 'e': case 'E':
    case 'i': case 'I':
    case 'o': case 'O':
    case 'u': case 'U':
        return true;
    }
    return false;
}

bool alternating_vowels_and_consonants(const char* str, size_t len) {
    for (size_t i = 1; i < len; ++i) {
        if (is_vowel(str[i]) == is_vowel(str[i - 1]))
            return false;
    }
    return true;
}

int main(int argc, char** argv) {
    const char* filename = argc < 2 ? "unixdict.txt" : argv[1];
    FILE* fp = fopen(filename, "r");
    if (!fp) {
        perror(filename);
        return EXIT_FAILURE;
    }
    char line[MAX_WORD_SIZE];
    int n = 1;
    while (fgets(line, sizeof(line), fp)) {
        size_t len = strlen(line) - 1; 
        if (len > 9 && alternating_vowels_and_consonants(line, len))
            printf("%2d: %s", n++, line);
    }
    fclose(fp);
    return EXIT_SUCCESS;
}

Go: package main

import (
    "bytes"
    "fmt"
    "io/ioutil"
    "log"
    "strings"
    "unicode/utf8"
)

func isVowel(c rune) bool { return strings.ContainsRune("aeiou", c) }

func main() {
    wordList := "unixdict.txt"
    b, err := ioutil.ReadFile(wordList)
    if err != nil {
        log.Fatal("Error reading file")
    }
    bwords := bytes.Fields(b)
    var words []string
    for _, bword := range bwords {
        s := string(bword)
        if utf8.RuneCountInString(s) > 9 {
            words = append(words, s)
        }
    }
    count := 0
    fmt.Println("Words with alternate consonants and vowels in", wordList, "\b:\n")
    for _, word := range words {
        found := true
        for i, c := range word {
            if (i%2 == 0 && isVowel(c)) || (i%2 == 1 && !isVowel(c)) {
                found = false
                break
            }
        }
        if !found {
            found = true
            for i, c := range word {
                if (i%2 == 0 && !isVowel(c)) || (i%2 == 1 && isVowel(c)) {
                    found = false
                    break
                }
            }
        }
        if found {
            count++
            fmt.Printf("%2d: %s\n", count, word)
        }
    }
}
Task: Find words with alternating vowels and consonants
C++: #include <cstdlib>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <string>

bool is_vowel(char ch) {
    switch (ch) {
    case 'a': case 'A':
    case 'e': case 'E':
    case 'i': case 'I':
    case 'o': case 'O':
    case 'u': case 'U':
        return true;
    }
    return false;
}

bool alternating_vowels_and_consonants(const std::string& str) {
    for (size_t i = 1, len = str.size(); i < len; ++i) {
        if (is_vowel(str[i]) == is_vowel(str[i - 1]))
            return false;
    }
    return true;
}

int main(int argc, char** argv) {
    const char* filename = argc < 2 ? "unixdict.txt" : argv[1];
    std::ifstream in(filename);
    if (!in) {
        std::cerr << "Cannot open file '" << filename << "'.\n";
        return EXIT_FAILURE;
    }
    std::string line;
    for (int n = 1; getline(in, line); ) {
        if (line.size() > 9 && alternating_vowels_and_consonants(line))
            std::cout << std::setw(2) << n++ << ": " << line << '\n';
    }
    return EXIT_SUCCESS;
}

Go: package main

import (
    "bytes"
    "fmt"
    "io/ioutil"
    "log"
    "strings"
    "unicode/utf8"
)

func isVowel(c rune) bool { return strings.ContainsRune("aeiou", c) }

func main() {
    wordList := "unixdict.txt"
    b, err := ioutil.ReadFile(wordList)
    if err != nil {
        log.Fatal("Error reading file")
    }
    bwords := bytes.Fields(b)
    var words []string
    for _, bword := range bwords {
        s := string(bword)
        if utf8.RuneCountInString(s) > 9 {
            words = append(words, s)
        }
    }
    count := 0
    fmt.Println("Words with alternate consonants and vowels in", wordList, "\b:\n")
    for _, word := range words {
        found := true
        for i, c := range word {
            if (i%2 == 0 && isVowel(c)) || (i%2 == 1 && !isVowel(c)) {
                found = false
                break
            }
        }
        if !found {
            found = true
            for i, c := range word {
                if (i%2 == 0 && !isVowel(c)) || (i%2 == 1 && isVowel(c)) {
                    found = false
                    break
                }
            }
        }
        if found {
            count++
            fmt.Printf("%2d: %s\n", count, word)
        }
    }
}
Task: Find words with alternating vowels and consonants
C++: #include <cstdlib>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <string>

bool is_vowel(char ch) {
    switch (ch) {
    case 'a': case 'A':
    case 'e': case 'E':
    case 'i': case 'I':
    case 'o': case 'O':
    case 'u': case 'U':
        return true;
    }
    return false;
}

bool alternating_vowels_and_consonants(const std::string& str) {
    for (size_t i = 1, len = str.size(); i < len; ++i) {
        if (is_vowel(str[i]) == is_vowel(str[i - 1]))
            return false;
    }
    return true;
}

int main(int argc, char** argv) {
    const char* filename = argc < 2 ? "unixdict.txt" : argv[1];
    std::ifstream in(filename);
    if (!in) {
        std::cerr << "Cannot open file '" << filename << "'.\n";
        return EXIT_FAILURE;
    }
    std::string line;
    for (int n = 1; getline(in, line); ) {
        if (line.size() > 9 && alternating_vowels_and_consonants(line))
            std::cout << std::setw(2) << n++ << ": " << line << '\n';
    }
    return EXIT_SUCCESS;
}

Python: 



def isLongAlternator(s):
    
    def p(a, b):
        return isVowel(a) != isVowel(b)
    return 9 < len(s) and all(map(p, s, s[1:]))


def isVowel(c):
    
    return c in 'aeiou'




def main():
    
    matches = [
        x for x in readFile('unixdict.txt').splitlines()
        if isLongAlternator(x)
    ]
    w = max(len(x) for x in matches)
    print(str(len(matches)) + ' matching words:\n')
    print(
        '\n'.join(
            ' '.join(s) for s in chunksOf(4)([
                x.ljust(w, ' ') for x in matches
            ])
        )
    )





def chunksOf(n):
    
    def go(xs):
        return (
            xs[i:n + i] for i in range(0, len(xs), n)
        ) if 0 < n else None
    return go



def readFile(fp):
    
    with open(fp, 'r', encoding='utf-8') as f:
        return f.read()



if __name__ == '__main__':
    main()
Task: Tonelli-Shanks algorithm
Go: package main

import "fmt"




func ts(n, p int) (R1, R2 int, ok bool) {
    
    powModP := func(a, e int) int {
        s := 1
        for ; e > 0; e-- {
            s = s * a % p
        }
        return s
    }
    
    ls := func(a int) int {
        return powModP(a, (p-1)/2)
    }
    
    if ls(n) != 1 {
        return 0, 0, false
    }
    
    
    Q := p - 1
    S := 0
    for Q&1 == 0 {
        S++
        Q >>= 1
    }
    
    if S == 1 {
        R1 = powModP(n, (p+1)/4)
        return R1, p - R1, true
    }
    
    z := 2
    for ; ls(z) != p-1; z++ {
    }
    c := powModP(z, Q)
    
    R := powModP(n, (Q+1)/2)
    t := powModP(n, Q)
    M := S
    
    for {
        
        if t == 1 {
            return R, p - R, true
        }
        
        i := 0
        for z := t; z != 1 && i < M-1; {
            z = z * z % p
            i++
        }
        
        b := c
        for e := M - i - 1; e > 0; e-- {
            b = b * b % p
        }
        R = R * b % p
        c = b * b % p 
        t = t * c % p
        M = i
    }
}

func main() {
    fmt.Println(ts(10, 13))
    fmt.Println(ts(56, 101))
    fmt.Println(ts(1030, 10009))
    fmt.Println(ts(1032, 10009))
    fmt.Println(ts(44402, 100049))
}

Python: def legendre(a, p):
    return pow(a, (p - 1) // 2, p)

def tonelli(n, p):
    assert legendre(n, p) == 1, "not a square (mod p)"
    q = p - 1
    s = 0
    while q % 2 == 0:
        q //= 2
        s += 1
    if s == 1:
        return pow(n, (p + 1) // 4, p)
    for z in range(2, p):
        if p - 1 == legendre(z, p):
            break
    c = pow(z, q, p)
    r = pow(n, (q + 1) // 2, p)
    t = pow(n, q, p)
    m = s
    t2 = 0
    while (t - 1) % p != 0:
        t2 = (t * t) % p
        for i in range(1, m):
            if (t2 - 1) % p == 0:
                break
            t2 = (t2 * t2) % p
        b = pow(c, 1 << (m - i - 1), p)
        r = (r * b) % p
        c = (b * b) % p
        t = (t * c) % p
        m = i
    return r

if __name__ == '__main__':
    ttest = [(10, 13), (56, 101), (1030, 10009), (44402, 100049),
	     (665820697, 1000000009), (881398088036, 1000000000039),
             (41660815127637347468140745042827704103445750172002, 10**50 + 577)]
    for n, p in ttest:
        r = tonelli(n, p)
        assert (r * r - n) % p == 0
        print("n = %d p = %d" % (n, p))
        print("\t  roots : %d %d" % (r, p - r))
Task: Stream merge
C: 

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>

#define GET(N) { if(fscanf(f##N,"%d",&b##N ) != 1) f##N = NULL; }
#define PUT(N) { printf("%d\n", b##N); GET(N) }

void merge(FILE* f1, FILE* f2, FILE* out)
{
    int b1;
    int b2;

    if(f1) GET(1)
    if(f2) GET(2)

    while ( f1 && f2 )
    {
        if ( b1 <= b2 ) PUT(1)
        else            PUT(2)
    }
    while (f1 ) PUT(1)
    while (f2 ) PUT(2)
}

int main(int argc, char* argv[])
{
    if ( argc < 3 || argc > 3 )
    {
        puts("streammerge filename1 filename2");
        exit(EXIT_FAILURE);
    }
    else
        merge(fopen(argv[1],"r"),fopen(argv[2],"r"),stdout);

    return EXIT_SUCCESS;
}

C#: using System;
using System.Collections.Generic;
using System.Linq;

namespace RosettaCode
{
    static class StreamMerge
    {
        static IEnumerable<T> Merge2<T>(IEnumerable<T> source1, IEnumerable<T> source2) where T : IComparable
        {
            var q1 = new Queue<T>(source1);
            var q2 = new Queue<T>(source2);
            while (q1.Any() && q2.Any())
            {
                var c = q1.Peek().CompareTo(q2.Peek());
                if (c <= 0) yield return q1.Dequeue(); else yield return q2.Dequeue();
            }
            while (q1.Any()) yield return q1.Dequeue();
            while (q2.Any()) yield return q2.Dequeue();
        }

        static IEnumerable<T> MergeN<T>(params IEnumerable<T>[] sources) where T : IComparable
        {
            var queues = sources.Select(e => new Queue<T>(e)).Where(q => q.Any()).ToList();
            var headComparer = Comparer<Queue<T>>.Create((x, y) => x.Peek().CompareTo(y.Peek()));
            queues.Sort(headComparer);
            
            while (queues.Any())
            {
                var q = queues.First();
                queues.RemoveAt(0);
                yield return q.Dequeue();
                if (q.Any())
                {
                    var index = queues.BinarySearch(q, headComparer);
                    queues.Insert(index < 0 ? ~index : index, q);
                }
            }
        }

        static void Main()
        {
            var a = new[] { 1, 4, 7, 10 };
            var b = new[] { 2, 5, 8, 11 };
            var c = new[] { 3, 6, 9, 12 };

            foreach (var i in Merge2(a, b)) Console.Write($"{i} ");
            Console.WriteLine();

            foreach (var i in MergeN(a, b, c)) Console.Write($"{i} ");
            Console.WriteLine();
        }
    }
}
Task: Stream merge
C: 

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>

#define GET(N) { if(fscanf(f##N,"%d",&b##N ) != 1) f##N = NULL; }
#define PUT(N) { printf("%d\n", b##N); GET(N) }

void merge(FILE* f1, FILE* f2, FILE* out)
{
    int b1;
    int b2;

    if(f1) GET(1)
    if(f2) GET(2)

    while ( f1 && f2 )
    {
        if ( b1 <= b2 ) PUT(1)
        else            PUT(2)
    }
    while (f1 ) PUT(1)
    while (f2 ) PUT(2)
}

int main(int argc, char* argv[])
{
    if ( argc < 3 || argc > 3 )
    {
        puts("streammerge filename1 filename2");
        exit(EXIT_FAILURE);
    }
    else
        merge(fopen(argv[1],"r"),fopen(argv[2],"r"),stdout);

    return EXIT_SUCCESS;
}

Go: package main

import (
    "container/heap"
    "fmt"
    "io"
    "log"
    "os"
    "strings"
)

var s1 = "3 14 15"
var s2 = "2 17 18"
var s3 = ""
var s4 = "2 3 5 7"

func main() {
    fmt.Print("merge2: ")
    merge2(
        os.Stdout,
        strings.NewReader(s1),
        strings.NewReader(s2))
    fmt.Println()

    fmt.Print("mergeN: ")
    mergeN(
        os.Stdout,
        strings.NewReader(s1),
        strings.NewReader(s2),
        strings.NewReader(s3),
        strings.NewReader(s4))
    fmt.Println()
}

func r1(r io.Reader) (v int, ok bool) {
    switch _, err := fmt.Fscan(r, &v); {
    case err == nil:
        return v, true
    case err != io.EOF:
        log.Fatal(err)
    }
    return
}

func merge2(m io.Writer, s1, s2 io.Reader) {
    v1, d1 := r1(s1)
    v2, d2 := r1(s2)
    var v int
    for d1 || d2 {
        if !d2 || d1 && v1 < v2 {
            v = v1
            v1, d1 = r1(s1)
        } else {
            v = v2
            v2, d2 = r1(s2)
        }
        fmt.Fprint(m, v, " ")
    }
}

type sv struct {
    s io.Reader
    v int
}

type sh []sv

func (s sh) Len() int            { return len(s) }
func (s sh) Less(i, j int) bool  { return s[i].v < s[j].v }
func (s sh) Swap(i, j int)       { s[i], s[j] = s[j], s[i] }
func (p *sh) Push(x interface{}) { *p = append(*p, x.(sv)) }
func (p *sh) Pop() interface{} {
    s := *p
    last := len(s) - 1
    v := s[last]
    *p = s[:last]
    return v
}

func mergeN(m io.Writer, s ...io.Reader) {
    var h sh
    for _, s := range s {
        if v, d := r1(s); d {
            h = append(h, sv{s, v})
        }
    }
    heap.Init(&h)
    for len(h) > 0 {
        p := heap.Pop(&h).(sv)
        fmt.Fprint(m, p.v, " ")
        if v, d := r1(p.s); d {
            heap.Push(&h, sv{p.s, v})
        }
    }
}
Task: Stream merge
C: 

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>

#define GET(N) { if(fscanf(f##N,"%d",&b##N ) != 1) f##N = NULL; }
#define PUT(N) { printf("%d\n", b##N); GET(N) }

void merge(FILE* f1, FILE* f2, FILE* out)
{
    int b1;
    int b2;

    if(f1) GET(1)
    if(f2) GET(2)

    while ( f1 && f2 )
    {
        if ( b1 <= b2 ) PUT(1)
        else            PUT(2)
    }
    while (f1 ) PUT(1)
    while (f2 ) PUT(2)
}

int main(int argc, char* argv[])
{
    if ( argc < 3 || argc > 3 )
    {
        puts("streammerge filename1 filename2");
        exit(EXIT_FAILURE);
    }
    else
        merge(fopen(argv[1],"r"),fopen(argv[2],"r"),stdout);

    return EXIT_SUCCESS;
}

Python: import heapq
import sys

sources = sys.argv[1:]
for item in heapq.merge(open(source) for source in sources):
    print(item)
Task: Stream merge
C++: 
#include <iostream>
#include <vector>

template <typename C, typename A>
void merge2(const C& c1, const C& c2, const A& action) {
    auto i1 = std::cbegin(c1);
    auto i2 = std::cbegin(c2);

    while (i1 != std::cend(c1) && i2 != std::cend(c2)) {
        if (*i1 <= *i2) {
            action(*i1);
            i1 = std::next(i1);
        } else {
            action(*i2);
            i2 = std::next(i2);
        }
    }
    while (i1 != std::cend(c1)) {
        action(*i1);
        i1 = std::next(i1);
    }
    while (i2 != std::cend(c2)) {
        action(*i2);
        i2 = std::next(i2);
    }
}

template <typename A, typename C>
void mergeN(const A& action, std::initializer_list<C> all) {
    using I = typename C::const_iterator;
    using R = std::pair<I, I>;

    std::vector<R> vit;
    for (auto& c : all) {
        auto p = std::make_pair(std::cbegin(c), std::cend(c));
        vit.push_back(p);
    }

    bool done;
    R* least;
    do {
        done = true;

        auto it = vit.begin();
        auto end = vit.end();
        least = nullptr;

        
        while (it != end && it->first == it->second) {
            it++;
        }
        if (it != end) {
            least = &(*it);
        }
        while (it != end) {
            
            while (it != end && it->first == it->second) {
                it++;
            }
            if (least != nullptr && it != end
                && it->first != it->second
                && *(it->first) < *(least->first)) {
                
                least = &(*it);
            }
            if (it != end) {
                it++;
            }
        }
        if (least != nullptr && least->first != least->second) {
            done = false;
            action(*(least->first));
            least->first = std::next(least->first);
        }
    } while (!done);
}

void display(int num) {
    std::cout << num << ' ';
}

int main() {
    std::vector<int> v1{ 0, 3, 6 };
    std::vector<int> v2{ 1, 4, 7 };
    std::vector<int> v3{ 2, 5, 8 };

    merge2(v2, v1, display);
    std::cout << '\n';

    mergeN(display, { v1 });
    std::cout << '\n';

    mergeN(display, { v3, v2, v1 });
    std::cout << '\n';
}

Python: import heapq
import sys

sources = sys.argv[1:]
for item in heapq.merge(open(source) for source in sources):
    print(item)
Task: Stream merge
C#: using System;
using System.Collections.Generic;
using System.Linq;

namespace RosettaCode
{
    static class StreamMerge
    {
        static IEnumerable<T> Merge2<T>(IEnumerable<T> source1, IEnumerable<T> source2) where T : IComparable
        {
            var q1 = new Queue<T>(source1);
            var q2 = new Queue<T>(source2);
            while (q1.Any() && q2.Any())
            {
                var c = q1.Peek().CompareTo(q2.Peek());
                if (c <= 0) yield return q1.Dequeue(); else yield return q2.Dequeue();
            }
            while (q1.Any()) yield return q1.Dequeue();
            while (q2.Any()) yield return q2.Dequeue();
        }

        static IEnumerable<T> MergeN<T>(params IEnumerable<T>[] sources) where T : IComparable
        {
            var queues = sources.Select(e => new Queue<T>(e)).Where(q => q.Any()).ToList();
            var headComparer = Comparer<Queue<T>>.Create((x, y) => x.Peek().CompareTo(y.Peek()));
            queues.Sort(headComparer);
            
            while (queues.Any())
            {
                var q = queues.First();
                queues.RemoveAt(0);
                yield return q.Dequeue();
                if (q.Any())
                {
                    var index = queues.BinarySearch(q, headComparer);
                    queues.Insert(index < 0 ? ~index : index, q);
                }
            }
        }

        static void Main()
        {
            var a = new[] { 1, 4, 7, 10 };
            var b = new[] { 2, 5, 8, 11 };
            var c = new[] { 3, 6, 9, 12 };

            foreach (var i in Merge2(a, b)) Console.Write($"{i} ");
            Console.WriteLine();

            foreach (var i in MergeN(a, b, c)) Console.Write($"{i} ");
            Console.WriteLine();
        }
    }
}

Python: import heapq
import sys

sources = sys.argv[1:]
for item in heapq.merge(open(source) for source in sources):
    print(item)
Task: Stream merge
Java: import java.util.Iterator;
import java.util.List;
import java.util.Objects;

public class StreamMerge {
    private static <T extends Comparable<T>> void merge2(Iterator<T> i1, Iterator<T> i2) {
        T a = null, b = null;

        while (i1.hasNext() || i2.hasNext()) {
            if (null == a && i1.hasNext()) {
                a = i1.next();
            }
            if (null == b && i2.hasNext()) {
                b = i2.next();
            }

            if (null != a) {
                if (null != b) {
                    if (a.compareTo(b) < 0) {
                        System.out.print(a);
                        a = null;
                    } else {
                        System.out.print(b);
                        b = null;
                    }
                } else {
                    System.out.print(a);
                    a = null;
                }
            } else if (null != b) {
                System.out.print(b);
                b = null;
            }
        }

        if (null != a) {
            System.out.print(a);
        }
        if (null != b) {
            System.out.print(b);
        }
    }

    @SuppressWarnings("unchecked")
    @SafeVarargs
    private static <T extends Comparable<T>> void mergeN(Iterator<T>... iter) {
        Objects.requireNonNull(iter);
        if (iter.length == 0) {
            throw new IllegalArgumentException("Must have at least one iterator");
        }

        Object[] pa = new Object[iter.length];
        boolean done;

        do {
            done = true;

            for (int i = 0; i < iter.length; i++) {
                Iterator<T> t = iter[i];
                if (null == pa[i] && t.hasNext()) {
                    pa[i] = t.next();
                }
            }

            T min = null;
            int idx = -1;
            for (int i = 0; i < pa.length; ++i) {
                T t = (T) pa[i];
                if (null != t) {
                    if (null == min) {
                        min = t;
                        idx = i;
                        done = false;
                    } else if (t.compareTo(min) < 0) {
                        min = t;
                        idx = i;
                        done = false;
                    }
                }
            }
            if (idx != -1) {
                System.out.print(min);
                pa[idx] = null;
            }
        } while (!done);
    }

    public static void main(String[] args) {
        List<Integer> l1 = List.of(1, 4, 7, 10);
        List<Integer> l2 = List.of(2, 5, 8, 11);
        List<Integer> l3 = List.of(3, 6, 9, 12);

        merge2(l1.iterator(), l2.iterator());
        System.out.println();

        mergeN(l1.iterator(), l2.iterator(), l3.iterator());
        System.out.println();
        System.out.flush();
    }
}

Python: import heapq
import sys

sources = sys.argv[1:]
for item in heapq.merge(open(source) for source in sources):
    print(item)