acwing每日一题-字符串删减

参考：https://www.acwing.com/solution/content/56819/

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;
int num,del;
int main(void) {
    int n;
    string s;
    cin >> n >> s;
    for(int i = 0;i<n;i++){
        if(s[i] == 'x'){
            num++;
            if(num == 3){
                num--;
                del++;
            }
        }else {
            num = 0;
        }
    }
    cout << del << " ";

}