1779A - Hall of Fame - CodeForces Solution

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <map>
#include <unordered_map>
#include <unordered_set>

typedef long long ll ;
typedef long double ld ;
typedef unsigned long long ull ;

typedef std::pair<int , int> pii ;
typedef std::pair<ll , ll> pll ;
typedef std::pair<ld , ld> pld ;

typedef std::vector<int> vi ;
typedef std::vector<char> vc ;
typedef std::vector<ll> vll ;
typedef std::vector<pii> vpi ;
typedef std::vector<pll> vpl ;

#define forn(i , a , b) for(int i = a ; i < b ; i ++)
#define sorn(i , a , b) for(int i = (a) - 1 ; i >= b ; i --)
#define rep(i , a) for(int i = 0 ; i < a ; i ++)

#define f first
#define s second
//#define endl "\n"
#define ins insert
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define sz(x) (int)(x).size()
#define all(tt) tt.begin() , tt.end()
#define read(x) scanf("%d", &x)

using namespace std ;

// int dx[4] = {1 , 0 , -1 , 0} ;
// int dy[4] = {0 , 1 , 0 , -1} ;

const int N = 2e5 + 10 ;
int a[N] , b[N] ;

int main ()
{
    std::ios::sync_with_stdio(false) ;
    std::cin.tie(0) ;
	std::cout.tie(0) ;
    
    int T ;
    cin >> T ;
    while (T --)
    {
        int n ;
        cin >> n ;
        string s ;
        cin >> s ;
        if(s == string(n, s[0]))
        {
            cout << "-1" << endl ;
            continue ;
        }
        int ans = -1 ;
        for(int i = 0 ; i < n - 1 ; i ++)
        {
            if(s[i] == 'R' && s[i + 1] == 'L')
            {
                ans = 0 ;
                break ;
            }
            if (s[i] == 'L' && s[i + 1] == 'R')
            {
                ans = i + 1 ;
                break ;
            }
        }
        cout << ans << endl ;
    }
    
	return 0 ;
}