Programming contest 101

No worries if you are new to programming contest, the only thing that is tricky to you, really, is you need to know how to get the inputs and output the results (I/O). Everything is through standard input/output (stdin/stdout). Here is a silly example, write a program that takes two integers and output the sum. 

(In C++)
#include <iostream>
using namespace::std;
int main()
{
       int a, b;
       cin >> a >> b;
       int c = a + b;
       cout << c << endl;
}

(In Python3)
import sys
a, b = sys.stdin.readline().split()
c = int(a) + int(b)
print(c)

(In Java -- make sure that you name the class Solution)
import java.io.*;
import java.util.*;
public class Solution {
       public static void main(String[] args) {
     	     Solution solution = new Solution();
	     Scanner in = new Scanner(System.in);
       	     int a = in.nextInt();
             int b = in.nextInt();
             System.out.println(a + b);
    	}
}

Practice websites

We recommend the following websites for you to get practice and get familiar with the programming contest.

A sample problem (easy)

Problem: Given an array of integers, find the sum of its elements.

Input Format
The first line contains an integer, n, denoting the size of the array. 
The second line contains  space-separated integers representing the array's elements.
Constraints: 0 < n and the elements < 1000

Output Format
Print the sum of the array's elements as a single integer.

Sample Input
6
1 2 3 4 10 11

Sample Output
31