Codeforces Round #238 (Div. 2), problem: (B) Domino Effect solution

Codeforces Round #238 (Div. 2), problem: (B) Domino Effect: http://codeforces.com/contest/405/problem/B

Codeforces Round #238 (Div. 2), problem: (B) Domino Effect solution: 

#include <iostream>
#include <cstdio>
using namespace std;

int main() {
    int n, r, l, ans, cnt;
    ans=cnt=r=l=0;
    char s[3005];
    scanf("%d", &n);
    scanf("%s", s);
    for(int i=0; i<n; i++) {
        if(s[i]=='.' && r==0) cnt++;
        if(s[i]=='L') {
            cnt=0;
            r=0;
        }
        if(s[i]=='R') {
            ans+=cnt;
            cnt=0;
            r=1;
        }
    }
    if(cnt>0) ans+=cnt, cnt=0;
    r=l=0;
    for(int i=0; i<n; i++) {
        if(s[i]=='R') r=1;
        if(s[i]=='.' && r==1) cnt++;
        if(s[i]=='L') {
            if(cnt%2==1) ans++;
            cnt=0;
            r=0;
        }
    }
    printf("%d", ans);
    return 0;
}