WeixiangYan/CodeTransOcean huggingface dataset:
Task: Pell's equation

C: #include <math.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

struct Pair {
    uint64_t v1, v2;
};

struct Pair makePair(uint64_t a, uint64_t b) {
    struct Pair r;
    r.v1 = a;
    r.v2 = b;
    return r;
}

struct Pair solvePell(int n) {
    int x = (int) sqrt(n);

    if (x * x == n) {
        
        return makePair(1, 0);
    } else {
        
        int y = x;
        int z = 1;
        int r = 2 * x;
        struct Pair e = makePair(1, 0);
        struct Pair f = makePair(0, 1);
        uint64_t a = 0;
        uint64_t b = 0;

        while (true) {
            y = r * z - y;
            z = (n - y * y) / z;
            r = (x + y) / z;
            e = makePair(e.v2, r * e.v2 + e.v1);
            f = makePair(f.v2, r * f.v2 + f.v1);
            a = e.v2 + x * f.v2;
            b = f.v2;
            if (a * a - n * b * b == 1) {
                break;
            }
        }

        return makePair(a, b);
    }
}

void test(int n) {
    struct Pair r = solvePell(n);
    printf("x^2 - %3d * y^2 = 1 for x = %21llu and y = %21llu\n", n, r.v1, r.v2);
}

int main() {
    test(61);
    test(109);
    test(181);
    test(277);

    return 0;
}







Python: import math

def solvePell(n):
    x = int(math.sqrt(n))
    y, z, r = x, 1, x << 1
    e1, e2 = 1, 0
    f1, f2 = 0, 1
    while True:
        y = r * z - y
        z = (n - y * y) // z
        r = (x + y) // z

        e1, e2 = e2, e1 + e2 * r
        f1, f2 = f2, f1 + f2 * r

        a, b = f2 * x + e2, f2
        if a * a - n * b * b == 1:
            return a, b

for n in [61, 109, 181, 277]:
    x, y = solvePell(n)
    print("x^2 - %3d * y^2 = 1 for x = %27d and y = %25d" % (n, x, y))
Task: Bulls and cows

C: #include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdbool.h>
#include <curses.h>
#include <string.h>

#define MAX_NUM_TRIES 72
#define LINE_BEGIN 7
#define LAST_LINE 18

int yp=LINE_BEGIN, xp=0;

char number[5];
char guess[5];

#define MAX_STR 256
void mvaddstrf(int y, int x, const char *fmt, ...)
{
  va_list args;
  char buf[MAX_STR];
  
  va_start(args, fmt);
  vsprintf(buf, fmt, args);
  move(y, x);
  clrtoeol();
  addstr(buf);
  va_end(args);
}

void ask_for_a_number()
{
  int i=0;
  char symbols[] = "123456789";

  move(5,0); clrtoeol();
  addstr("Enter four digits: ");
  while(i<4) {
    int c = getch();
    if ( (c >= '1') && (c <= '9') && (symbols[c-'1']!=0) ) {
      addch(c);
      symbols[c-'1'] = 0;
      guess[i++] = c;
    }
  }
}

void choose_the_number()
{
  int i=0, j;
  char symbols[] = "123456789";

  while(i<4) {
    j = rand() % 9;
    if ( symbols[j] != 0 ) {
      number[i++] = symbols[j];
      symbols[j] = 0;
    }
  }
}







Python: 

import random

digits = '123456789'
size = 4
chosen = ''.join(random.sample(digits,size))

print  % (size, size)
guesses = 0
while True:
    guesses += 1
    while True:
        
        guess = raw_input('\nNext guess [%i]: ' % guesses).strip()
        if len(guess) == size and \
           all(char in digits for char in guess) \
           and len(set(guess)) == size:
            break
        print "Problem, try again. You need to enter %i unique digits from 1 to 9" % size
    if guess == chosen:
        print '\nCongratulations you guessed correctly in',guesses,'attempts'
        break
    bulls = cows = 0
    for i in range(size):
        if guess[i] == chosen[i]:
            bulls += 1
        elif guess[i] in chosen:
            cows += 1
    print '  %i Bulls\n  %i Cows' % (bulls, cows)
Task: Sorting algorithms_Bubble sort

C: #include <stdio.h>

void bubble_sort (int *a, int n) {
    int i, t, j = n, s = 1;
    while (s) {
        s = 0;
        for (i = 1; i < j; i++) {
            if (a[i] < a[i - 1]) {
                t = a[i];
                a[i] = a[i - 1];
                a[i - 1] = t;
                s = 1;
            }
        }
        j--;
    }
}

int main () {
    int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1};
    int n = sizeof a / sizeof a[0];
    int i;
    for (i = 0; i < n; i++)
        printf("%d%s", a[i], i == n - 1 ? "\n" : " ");
    bubble_sort(a, n);
    for (i = 0; i < n; i++)
        printf("%d%s", a[i], i == n - 1 ? "\n" : " ");
    return 0;
}







Python: def bubble_sort(seq):
    
    changed = True
    while changed:
        changed = False
        for i in range(len(seq) - 1):
            if seq[i] > seq[i+1]:
                seq[i], seq[i+1] = seq[i+1], seq[i]
                changed = True
    return seq

if __name__ == "__main__":
   

   from random import shuffle

   testset = [_ for _ in range(100)]
   testcase = testset.copy() 
   shuffle(testcase)
   assert testcase != testset  
   bubble_sort(testcase)
   assert testcase == testset
Task: Product of divisors

C: #include <math.h>
#include <stdio.h>


unsigned int divisor_count(unsigned int n) {
    unsigned int total = 1;
    unsigned int p;

    
    for (; (n & 1) == 0; n >>= 1) {
        ++total;
    }
    
    for (p = 3; p * p <= n; p += 2) {
        unsigned int count = 1;
        for (; n % p == 0; n /= p) {
            ++count;
        }
        total *= count;
    }
    
    if (n > 1) {
        total *= 2;
    }
    return total;
}


unsigned int divisor_product(unsigned int n) {
    return pow(n, divisor_count(n) / 2.0);
}

int main() {
    const unsigned int limit = 50;
    unsigned int n;

    printf("Product of divisors for the first %d positive integers:\n", limit);
    for (n = 1; n <= limit; ++n) {
        printf("%11d", divisor_product(n));
        if (n % 5 == 0) {
            printf("\n");
        }
    }

    return 0;
}







Python: def product_of_divisors(n):
    assert(isinstance(n, int) and 0 < n)
    ans = i = j = 1
    while i*i <= n:
        if 0 == n%i:
            ans *= i
            j = n//i
            if j != i:
                ans *= j
        i += 1
    return ans
    
if __name__ == "__main__":
    print([product_of_divisors(n) for n in range(1,51)])
Task: File input_output

C: #include <stdio.h>

int main(int argc, char **argv) {
  FILE *in, *out;
  int c;

  in = fopen("input.txt", "r");
  if (!in) {
    fprintf(stderr, "Error opening input.txt for reading.\n");
    return 1;
  }

  out = fopen("output.txt", "w");
  if (!out) {
    fprintf(stderr, "Error opening output.txt for writing.\n");
    fclose(in);
    return 1;
  }

  while ((c = fgetc(in)) != EOF) {
    fputc(c, out);
  }

  fclose(out);
  fclose(in);
  return 0;
}







Python: import shutil
shutil.copyfile('input.txt', 'output.txt')
Task: Arithmetic_Integer

C: #include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
  int a, b;
  if (argc < 3) exit(1);
  b = atoi(argv[--argc]);
  if (b == 0) exit(2);
  a = atoi(argv[--argc]);
  printf("a+b = %d\n", a+b);
  printf("a-b = %d\n", a-b);
  printf("a*b = %d\n", a*b);
  printf("a/b = %d\n", a/b); 
  printf("a%%b = %d\n", a%b); 
  return 0;
}







Python: x = int(raw_input("Number 1: "))
y = int(raw_input("Number 2: "))

print "Sum: %d" % (x + y)
print "Difference: %d" % (x - y)
print "Product: %d" % (x * y)
print "Quotient: %d" % (x / y)     
                                   
print "Remainder: %d" % (x % y)    
print "Quotient: %d with Remainder: %d" % divmod(x, y)
print "Power: %d" % x**y


raw_input( )
Task: Matrix transposition

C: #include <stdio.h>

void transpose(void *dest, void *src, int src_h, int src_w)
{
	int i, j;
	double (*d)[src_h] = dest, (*s)[src_w] = src;
	for (i = 0; i < src_h; i++)
		for (j = 0; j < src_w; j++)
			d[j][i] = s[i][j];
}

int main()
{
	int i, j;
	double a[3][5] = {{ 0, 1, 2, 3, 4 },
			  { 5, 6, 7, 8, 9 },
			  { 1, 0, 0, 0, 42}};
	double b[5][3];
	transpose(b, a, 3, 5);

	for (i = 0; i < 5; i++)
		for (j = 0; j < 3; j++)
			printf("%g%c", b[i][j], j == 2 ? '\n' : ' ');
	return 0;
}







Python: m=((1,  1,  1,   1),
   (2,  4,  8,  16),
   (3,  9, 27,  81),
   (4, 16, 64, 256),
   (5, 25,125, 625))
print(zip(*m))
Task: Man or boy test

C: 
#include <stdio.h>
#include <stdlib.h>


typedef struct arg
{
  int       (*fn)(struct arg*);
  int        *k;
  struct arg *x1, *x2, *x3, *x4, *x5;
} ARG;


int f_1 (ARG* _) { return -1; }
int f0  (ARG* _) { return  0; }
int f1  (ARG* _) { return  1; }


int eval(ARG* a) { return a->fn(a); }
#define MAKE_ARG(...) (&(ARG){__VA_ARGS__})
#define FUN(...) MAKE_ARG(B, &k, __VA_ARGS__)

int A(ARG*);


int B(ARG* a)
{
  int k = *a->k -= 1;
  return A(FUN(a, a->x1, a->x2, a->x3, a->x4));
}

int A(ARG* a)
{
  return *a->k <= 0 ? eval(a->x4) + eval(a->x5) : B(a);
}

int main(int argc, char **argv)
{
  int k = argc == 2 ? strtol(argv[1], 0, 0) : 10;
  printf("%d\n", A(FUN(MAKE_ARG(f1), MAKE_ARG(f_1), MAKE_ARG(f_1),
                       MAKE_ARG(f1), MAKE_ARG(f0))));
  return 0;
}







Python: 
import sys
sys.setrecursionlimit(1025)

def a(in_k, x1, x2, x3, x4, x5):
    k = [in_k]
    def b():
        k[0] -= 1
        return a(k[0], b, x1, x2, x3, x4)
    return x4() + x5() if k[0] <= 0 else b()

x = lambda i: lambda: i
print(a(10, x(1), x(-1), x(-1), x(1), x(0)))
Task: Short-circuit evaluation

C: #include <stdio.h>
#include <stdbool.h>

bool a(bool in)
{
  printf("I am a\n");
  return in;
}

bool b(bool in)
{
  printf("I am b\n");
  return in;
}

#define TEST(X,Y,O)						\
  do {								\
    x = a(X) O b(Y);						\
    printf(#X " " #O " " #Y " = %s\n\n", x ? "true" : "false");	\
  } while(false);

int main()
{
  bool x;

  TEST(false, true, &&); 
  TEST(true, false, ||); 
  TEST(true, false, &&); 
  TEST(false, false, ||); 

  return 0;
}







Python: >>> def a(answer):
	print("  
	return answer

>>> def b(answer):
	print("  
	return answer

>>> for i in (False, True):
	for j in (False, True):
		print ("\nCalculating: x = a(i) and b(j)")
		x = a(i) and b(j)
		print ("Calculating: y = a(i) or  b(j)")
		y = a(i) or  b(j)

		

Calculating: x = a(i) and b(j)
  
Calculating: y = a(i) or  b(j)
  
  

Calculating: x = a(i) and b(j)
  
Calculating: y = a(i) or  b(j)
  
  

Calculating: x = a(i) and b(j)
  
  
Calculating: y = a(i) or  b(j)
  

Calculating: x = a(i) and b(j)
  
  
Calculating: y = a(i) or  b(j)
Task: Find limit of recursion

C: #include <stdio.h>

void recurse(unsigned int i)
{
  printf("%d\n", i);
  recurse(i+1); 
}

int main()
{
  recurse(0);
  return 0;
}







Python: import sys
print(sys.getrecursionlimit())
Task: Carmichael 3 strong pseudoprimes

C: #include <stdio.h>


#define mod(n,m) ((((n) % (m)) + (m)) % (m))

int is_prime(unsigned int n)
{
    if (n <= 3) {
        return n > 1;
    }
    else if (!(n % 2) || !(n % 3)) {
        return 0;
    }
    else {
        unsigned int i;
        for (i = 5; i*i <= n; i += 6)
            if (!(n % i) || !(n % (i + 2)))
                return 0;
        return 1;
    }
}

void carmichael3(int p1)
{
    if (!is_prime(p1)) return;

    int h3, d, p2, p3;
    for (h3 = 1; h3 < p1; ++h3) {
        for (d = 1; d < h3 + p1; ++d) {
            if ((h3 + p1)*(p1 - 1) % d == 0 && mod(-p1 * p1, h3) == d % h3) {
                p2 = 1 + ((p1 - 1) * (h3 + p1)/d);
                if (!is_prime(p2)) continue;
                p3 = 1 + (p1 * p2 / h3);
                if (!is_prime(p3) || (p2 * p3) % (p1 - 1) != 1) continue;
                printf("%d %d %d\n", p1, p2, p3);
            }
        }
    }
}

int main(void)
{
    int p1;
    for (p1 = 2; p1 < 62; ++p1)
        carmichael3(p1);
    return 0;
}







Python: class Isprime():
    
    multiples = {2}
    primes = [2]
    nmax = 2
    
    def __init__(self, nmax):
        if nmax > self.nmax:
            self.check(nmax)

    def check(self, n):
        if type(n) == float:
            if not n.is_integer(): return False
            n = int(n)
        multiples = self.multiples
        if n <= self.nmax:
            return n not in multiples
        else:
            
            primes, nmax = self.primes, self.nmax
            newmax = max(nmax*2, n)
            for p in primes:
                multiples.update(range(p*((nmax + p + 1) // p), newmax+1, p))
            for i in range(nmax+1, newmax+1):
                if i not in multiples:
                    primes.append(i)
                    multiples.update(range(i*2, newmax+1, i))
            self.nmax = newmax
            return n not in multiples

    __call__ = check
            
        
def carmichael(p1):
    ans = []
    if isprime(p1):
        for h3 in range(2, p1):
            g = h3 + p1
            for d in range(1, g):
                if (g * (p1 - 1)) % d == 0 and (-p1 * p1) % h3 == d % h3:
                    p2 = 1 + ((p1 - 1)* g // d)
                    if isprime(p2):
                        p3 = 1 + (p1 * p2 // h3)
                        if isprime(p3):
                            if (p2 * p3) % (p1 - 1) == 1:
                                
                                ans += [tuple(sorted((p1, p2, p3)))]
    return ans
                
isprime = Isprime(2)
 
ans = sorted(sum((carmichael(n) for n in range(62) if isprime(n)), []))
print(',\n'.join(repr(ans[i:i+5])[1:-1] for i in range(0, len(ans)+1, 5)))
Task: Image noise

C: #include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <SDL/SDL.h>
 
unsigned int frames = 0;
unsigned int t_acc = 0;
 
void print_fps ()
{
  static Uint32 last_t = 0;
  Uint32 t = SDL_GetTicks();
  Uint32 dt = t - last_t;
  t_acc += dt;
  if (t_acc > 1000)
  {
    unsigned int el_time = t_acc / 1000;
    printf("- fps: %g\n",
            (float) frames / (float) el_time);
    t_acc = 0;
    frames = 0;
  }
  last_t = t;
}
 
void blit_noise(SDL_Surface *surf)
{
  unsigned int i;
  long dim = surf->w * surf->h;
  while (1)
  {
    SDL_LockSurface(surf);
    for (i=0; i < dim; ++i) {
      ((unsigned char *)surf->pixels)[i] = ((rand() & 1) ? 255 : 0);
    }
    SDL_UnlockSurface(surf);
    SDL_Flip(surf);
    ++frames;
    print_fps();
  }
}
 
int main(void)
{
  SDL_Surface *surf = NULL;
  srand((unsigned int)time(NULL));
  SDL_Init(SDL_INIT_TIMER | SDL_INIT_VIDEO);
  surf = SDL_SetVideoMode(320, 240, 8, SDL_DOUBLEBUF | SDL_HWSURFACE);
  blit_noise(surf);
}







Python: black = color(0)
white = color(255)

def setup():
    size(320, 240)
    


def draw():
    loadPixels()
    for i in range(len(pixels)):
        if random(1) < 0.5:
            pixels[i] = black
        else:
            pixels[i] = white

    updatePixels()
    fill(0, 128)
    rect(0, 0, 60, 20)
    fill(255)
    text(frameRate, 5, 15)
Task: Keyboard input_Obtain a Y or N response

C: #include <stdio.h>
#include <termios.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/time.h>
 
void set_mode(int want_key)
{
	static struct termios old, new;
	if (!want_key) {
		tcsetattr(STDIN_FILENO, TCSANOW, &old);
		return;
	}
 
	tcgetattr(STDIN_FILENO, &old);
	new = old;
	new.c_lflag &= ~(ICANON);
	tcsetattr(STDIN_FILENO, TCSANOW, &new);
}
 
int get_key(int no_timeout)
{
	int c = 0;
	struct timeval tv;
	fd_set fs;
	tv.tv_usec = tv.tv_sec = 0;
 
	FD_ZERO(&fs);
	FD_SET(STDIN_FILENO, &fs);

	select(STDIN_FILENO + 1, &fs, 0, 0, no_timeout ? 0 : &tv);
	if (FD_ISSET(STDIN_FILENO, &fs)) {
		c = getchar();
		set_mode(0);
	}
	return c;
}
 
int main()
{
	int c;
	while(1) {
		set_mode(1);
		while (get_key(0)); 
		printf("Prompt again [Y/N]? ");
		fflush(stdout);

		c = get_key(1);
		if (c == 'Y' || c == 'y') {
			printf("\n");
			continue;
		}

		if (c == 'N' || c == 'n') {
			printf("\nDone\n");
			break;
		}

		printf("\nYes or no?\n");
	}

	return 0;
}







Python: 

try:
    from msvcrt import getch
except ImportError:
    def getch():
        import sys, tty, termios
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch

print "Press Y or N to continue"
while True:
    char = getch()
    if char.lower() in ("y", "n"):
        print char
        break
Task: Perfect numbers

C: #include "stdio.h"
#include "math.h"

int perfect(int n) {
    int max = (int)sqrt((double)n) + 1;
    int tot = 1;
    int i;

    for (i = 2; i < max; i++)
        if ( (n % i) == 0 ) {
            tot += i;
            int q = n / i;
            if (q > i)
                tot += q;
        }

    return tot == n;
}

int main() {
    int n;
    for (n = 2; n < 33550337; n++)
        if (perfect(n))
            printf("%d\n", n);

    return 0;
}







Python: def perf1(n):
    sum = 0
    for i in range(1, n):
        if n % i == 0:
            sum += i
    return sum == n
Task: Jacobsthal numbers

C: #include <stdio.h>
#include <gmp.h>

void jacobsthal(mpz_t r, unsigned long n) {
    mpz_t s;
    mpz_init(s);
    mpz_set_ui(r, 1);
    mpz_mul_2exp(r, r, n);
    mpz_set_ui(s, 1);
    if (n % 2) mpz_neg(s, s);
    mpz_sub(r, r, s);
    mpz_div_ui(r, r, 3);
}

void jacobsthal_lucas(mpz_t r, unsigned long n) {
    mpz_t a;
    mpz_init(a);
    mpz_set_ui(r, 1);
    mpz_mul_2exp(r, r, n);
    mpz_set_ui(a, 1);
    if (n % 2) mpz_neg(a, a);
    mpz_add(r, r, a);
}

int main() {
    int i, count;
    mpz_t jac[30], j;
    printf("First 30 Jacobsthal numbers:\n");
    for (i = 0; i < 30; ++i) {
        mpz_init(jac[i]);
        jacobsthal(jac[i], i);
        gmp_printf("%9Zd ", jac[i]);
        if (!((i+1)%5)) printf("\n");
    }

    printf("\nFirst 30 Jacobsthal-Lucas numbers:\n");
    mpz_init(j);
    for (i = 0; i < 30; ++i) {
        jacobsthal_lucas(j, i);
        gmp_printf("%9Zd ", j);
        if (!((i+1)%5)) printf("\n");
    }

    printf("\nFirst 20 Jacobsthal oblong numbers:\n");
    for (i = 0; i < 20; ++i) {
        mpz_mul(j, jac[i], jac[i+1]);
        gmp_printf("%11Zd ", j);
        if (!((i+1)%5)) printf("\n");
    }

    printf("\nFirst 20 Jacobsthal primes:\n");
    for (i = 0, count = 0; count < 20; ++i) {
        jacobsthal(j, i);
        if (mpz_probab_prime_p(j, 15) > 0) {
            gmp_printf("%Zd\n", j);
            ++count;
        }
    }

    return 0;
}







Python: 
from math import floor, pow

def isPrime(n):
    for i in range(2, int(n**0.5) + 1):
        if n % i == 0:
            return False        
    return True

def odd(n):
    return n and 1 != 0
    
def jacobsthal(n):
    return floor((pow(2,n)+odd(n))/3)

def jacobsthal_lucas(n):
    return int(pow(2,n)+pow(-1,n))

def jacobsthal_oblong(n):
    return jacobsthal(n)*jacobsthal(n+1)


if __name__ == '__main__':
    print("First 30 Jacobsthal numbers:")
    for j in range(0, 30):
        print(jacobsthal(j), end="  ")

    print("\n\nFirst 30 Jacobsthal-Lucas numbers: ")
    for j in range(0, 30):
        print(jacobsthal_lucas(j), end = '\t')

    print("\n\nFirst 20 Jacobsthal oblong numbers: ")
    for j in range(0, 20):
        print(jacobsthal_oblong(j), end="  ")

    print("\n\nFirst 10 Jacobsthal primes: ")
    for j in range(3, 33):
        if isPrime(jacobsthal(j)):
            print(jacobsthal(j))
Task: Sorting algorithms_Bead sort

C: #include <stdio.h>
#include <stdlib.h>

void bead_sort(int *a, int len)
{
	int i, j, max, sum;
	unsigned char *beads;
#	define BEAD(i, j) beads[i * max + j]

	for (i = 1, max = a[0]; i < len; i++)
		if (a[i] > max) max = a[i];

	beads = calloc(1, max * len);

	
	for (i = 0; i < len; i++)
		for (j = 0; j < a[i]; j++)
			BEAD(i, j) = 1;

	for (j = 0; j < max; j++) {
		
		for (sum = i = 0; i < len; i++) {
			sum += BEAD(i, j);
			BEAD(i, j) = 0;
		}
		
		for (i = len - sum; i < len; i++) BEAD(i, j) = 1;
	}

	for (i = 0; i < len; i++) {
		for (j = 0; j < max && BEAD(i, j); j++);
		a[i] = j;
	}
	free(beads);
}

int main()
{
	int i, x[] = {5, 3, 1, 7, 4, 1, 1, 20};
	int len = sizeof(x)/sizeof(x[0]);

	bead_sort(x, len);
	for (i = 0; i < len; i++)
		printf("%d\n", x[i]);

	return 0;
}







Python: 
from itertools import zip_longest


def beadsort(l):
    return list(map(sum, zip_longest(*[[1] * e for e in l], fillvalue=0)))



print(beadsort([5,3,1,7,4,1,1]))
Task: Arbitrary-precision integers (included)

C: #include <gmp.h>
#include <stdio.h>
#include <string.h>

int main()
{
	mpz_t a;
	mpz_init_set_ui(a, 5);
	mpz_pow_ui(a, a, 1 << 18); 

	int len = mpz_sizeinbase(a, 10);
	printf("GMP says size is: %d\n", len);

	
	char *s = mpz_get_str(0, 10, a);
	printf("size really is %d\n", len = strlen(s));
	printf("Digits: %.20s...%s\n", s, s + len - 20);

	
	return 0;
}







Python: >>> y = str( 5**4**3**2 )
>>> print ("5**4**3**2 = %s...%s and has %i digits" % (y[:20], y[-20:], len(y)))
5**4**3**2 = 62060698786608744707...92256259918212890625 and has 183231 digits
Task: Draw a sphere

C: #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>

const char *shades = ".:!*oe&#%@";

double light[3] = { 30, 30, -50 };
void normalize(double * v)
{
        double len = sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
        v[0] /= len; v[1] /= len; v[2] /= len;
}

double dot(double *x, double *y)
{
        double d = x[0]*y[0] + x[1]*y[1] + x[2]*y[2];
        return d < 0 ? -d : 0;
}

void draw_sphere(double R, double k, double ambient)
{
        int i, j, intensity;
        double b;
        double vec[3], x, y;
        for (i = floor(-R); i <= ceil(R); i++) {
                x = i + .5;
                for (j = floor(-2 * R); j <= ceil(2 * R); j++) {
                        y = j / 2. + .5;
                        if (x * x + y * y <= R * R) {
                                vec[0] = x;
                                vec[1] = y;
                                vec[2] = sqrt(R * R - x * x - y * y);
                                normalize(vec);
                                b = pow(dot(light, vec), k) + ambient;
                                intensity = (1 - b) * (sizeof(shades) - 1);
                                if (intensity < 0) intensity = 0;
                                if (intensity >= sizeof(shades) - 1)
                                        intensity = sizeof(shades) - 2;
                                putchar(shades[intensity]);
                        } else
                                putchar(' ');
                }
                putchar('\n');
        }
}


int main()
{
        normalize(light);
        draw_sphere(20, 4, .1);
        draw_sphere(10, 2, .4);

        return 0;
}







Python: import math

shades = ('.',':','!','*','o','e','&','

def normalize(v):
	len = math.sqrt(v[0]**2 + v[1]**2 + v[2]**2)
	return (v[0]/len, v[1]/len, v[2]/len)

def dot(x,y):
	d = x[0]*y[0] + x[1]*y[1] + x[2]*y[2]
	return -d if d < 0 else 0

def draw_sphere(r, k, ambient, light):
	for i in range(int(math.floor(-r)),int(math.ceil(r)+1)):
		x = i + 0.5
		line = ''

		for j in range(int(math.floor(-2*r)),int(math.ceil(2*r)+1)):
			y = j/2 + 0.5
			if x*x + y*y <= r*r:
				vec = normalize((x,y,math.sqrt(r*r - x*x - y*y)))
				b = dot(light,vec)**k + ambient
				intensity = int((1-b)*(len(shades)-1))
				line += shades[intensity] if 0 <= intensity < len(shades) else shades[0]
			else:
				line += ' '

		print(line)

light = normalize((30,30,-50))
draw_sphere(20,4,0.1, light)
draw_sphere(10,2,0.4, light)
Task: Least common multiple

C: #include <stdio.h>

int gcd(int m, int n)
{
        int tmp;
        while(m) { tmp = m; m = n % m; n = tmp; }       
        return n;
}

int lcm(int m, int n)
{
        return m / gcd(m, n) * n;
}

int main()
{
        printf("lcm(35, 21) = %d\n", lcm(21,35));
        return 0;
}







Python: >>> import fractions
>>> def lcm(a,b): return abs(a * b) / fractions.gcd(a,b) if a and b else 0

>>> lcm(12, 18)
36
>>> lcm(-6, 14)
42
>>> assert lcm(0, 2) == lcm(2, 0) == 0
>>>