Covid Run.cpp

Task: Covid-19 is spreading fast! There are N cities, numbered from 0 to (N−1), arranged in a circular manner. City 0 is connected to city 1, 1 to 2, …, city (N−2) to city (N−1), and city (N−1) to city 0

.

The virus is currently at city X
. Each day, it jumps from its current city, to the city K to its right, i.e., from city X to the city (X+K)%N. As the virus jumps, the cities in between don't get infected. Cities once infected stay infected. You live in city Y

. Find if it will reach your city eventually. If it will, print YES, else print NO.
Input:

    The first line of the input consists of an integer T

, the number of test cases.
The first and only line of each test case contains four space-separated integers - N
, K, X and Y

    , denoting the number of cities, the size of jumps, Covid's current city, and the city that you live in, respectively.

Output:

For each test case, in a new line, print YES if Covid shall reach your city after a finite number of days, else print NO.
Constraints

    1≤T≤100

1≤N≤1000
0≤X,Y≤N−1
0≤K≤1000

Subtasks

    Subtask 1 - 100% - Original constraints

Sample Input:

2
6 2 5 3
12 3 4 2

Sample Output:

YES
NO


Solution:



#include <iostream>
using namespace std;

int main(){
    int t;
    cin>>t;
    for(int i=0;i<t;i++){
        int n,k,x,y,a,flag=0;
        cin>>n>>k>>x>>y;
        if(x==y){
            flag =1;
        }
        else{
            a = x;
            x = (x+k)%n;
            while(x!=a){
                if(x==y){
                    flag = 1;
                    break;
                }
                else{
                    x = (x+k)%n;
                }
            }
        }
        if(flag==0){
            cout<<"NO"<<endl;
        }
        else{
            cout<<"YES"<<endl;
        }
    }
    return 0;
}