count-my-colors.cc

#include <stdio.h>

int main () {
    long long n, m;
    scanf("%lld %lld", &n, &m);

    const long long MOD = 17e7; // same as 17x10^7
    long long ans = m; 
    // or ans = 1 and for(int i = 0; i < n; i++)
    
    for(int i = 1; i < n; i++) {
        ans = (ans * m) % MOD;
    }
    
    printf("%lld\n", ans);

}

kerollos-and-os.cc

#include <stdio.h>

int main()
{
    int n;
    scanf("%d", &n);
    double wait[n]; // one of (wait or burst) must be double "because int division => int"
    int burst[n];
    double max_response_time = 0;
    for (int i = 0; i < n; i++)
        scanf("%lf", &wait[i]);

    for (int i = 0; i < n; i++)
    {
        scanf("%d", &burst[i]);
        double process_response_time =  (wait[i] + burst[i]) / burst[i];
        
        if (process_response_time > max_response_time)
            max_response_time = process_response_time;
    }
    printf("%.6f\n", max_response_time);
}

khaled-cheating.cc

#include <iostream>
using namespace std;
 
int main()
{
	int n;
	cin >> n;
	int form2[n];/// order of questions in form2
	for(int i = 0; i < n; i++)
		cin >> form2[i];
	char answer[n];/// answers of questions from 1-n 
	/// note array index from 0 -> n-1 which means answer[0] is question 1
	for(int i = 0; i < n; i++)
		cin >> answer[i];
	for(int i = 0; i < n; i++){/// loop on form2 questions
		int current_question = form2[i];
		char current_answer = answer[current_question - 1];/// -1 to make it zero based
		cout << current_answer << " ";
	}
	return 0;
}
 

koko-hair.cc

#include <stdio.h>

int score (int n){
    int number_of_operations = 0;

    while(n != 1){
        if(n % 2 == 0) {
            n /= 2;
        }else {
            n = 3 * n + 1;
        }
        number_of_operations++;
    }

    return number_of_operations;

}

int main () {
    int r, k;
    scanf("%d %d", &r, &k);
    
    int rokaia_score = score(r);
    int koko_score = score(k);

    if(rokaia_score >= koko_score)
        printf("Rokaia wins!\n");
    else 
        printf("Koko wins!\n");

}

whatever.cc

#include <stdio.h>

int main () {
  char x, y;
  scanf("%c %c", &x, &y); // cin >> x >> y;
  printf("%c%c\n", x, y); // cout << x << y << endl;
}

who-gets-it-first.cc

#include <stdio.h>

int main () {
    int n; 
    scanf("%d", &n);
    char students[n][106]; 
    // 106 because the max length of the name is 105 "don't forget the null char"
    // or  You can use "string studnets[n];" in C++
    for(int i = 0; i < n; i++)
        scanf("%s", students[i]);
    
    for(int i = n-1; i >= 0; i--)
        printf("%s\n", students[i]);
}