stdin/stdout templates:


Python2:
----------------------------------------------------
# Multiple-line input, like:
# https://www.facebook.com/hackercup/problem/169401886867367/

# total case number
# element count for Case 1 (3)
# Case 1: element 1
# Case 1: element 2
# Case 1: element 3
# element count for Case 2 (2)
# Case 2: element 1
# Case 2: element 2

import sys

input = sys.stdin.readlines()

if int(input[0].strip('\n')) == 0:
    exit(0)

marker = 1
count = 1

while marker < len(input):
    
    l = []
    result = 0
    
    for i in xrange(marker+1, marker+int(input[marker])+1):
        l.append(int(input[i].strip('\n')))
    
    length = int(input[marker].strip('\n'))
    print 'length', length
    print 'list', l
    
    # do something
    
    print 'Case #'+str(count)+':', result
    marker = marker+int(input[marker].strip('\n'))+1
    count += 1
    print

----------------------------------------------------

# Simple one

import sys

input = sys.stdin.readlines()

#input = sys.stdin.read()

#for line in input:
    #print line

for i in xrange(len(input)):
    s = input[i].strip('\n')
    print s

#sys.stdout.write(input) # no new line

----------------------------------------------------



C++:
----------------------------------------------------

#include <iostream>

using namespace std;

int main()
{
    string s;

    cin >> s;

    cout << s;
    //cout << s << endl;
    return 0;
}

----------------------------------------------------



C:
----------------------------------------------------

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

main()

{
    char *s = (char *) malloc(1000 * sizeof(char));
    scanf("%s",s);
    printf("%s", s);


    // if number:
    int m,n;
    while (scanf("%d %d\n",&m,&n)==2){  // read 2 integers
        ...
    }
}

----------------------------------------------------



Java:
----------------------------------------------------

import java.io.*;
import java.util.Scanner;

public class Test{

    public static void main(String []args) {
         
        Scanner stdin = new Scanner(System.in);
      
        while(stdin.hasNextLine()) {
            String line = stdin.nextLine();
            String[] tokens = line.split(" ");
            System.out.print(Integer.parseInt(tokens[0]));
            //System.out.println(Integer.parseInt(tokens[0]));
        }
    }
}

----------------------------------------------------

===============================
Generate prime numbers fast:
----------------------------------------------------

l = []

def sieve_for_primes_to(n):
    size = n//2
    sieve = [1]*size
    limit = int(n**0.5)
    for i in range(1,limit):
        if sieve[i]:
            val = 2*i+1
            tmp = ((size-1) - i)//val 
            sieve[i+val::val] = [0]*tmp
    return [2] + [i*2+1 for i, v in enumerate(sieve) if v and i>0]

l = sieve_for_primes_to(n)
# print l

===============================
Check if a number (n) is a palindrome:

if str(n) == str(n)[::-1]:
===============================