570C - Replacement - CodeForces Solution

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,q,counter=0;
    cin>>n>>q;
    string x;
    cin>>x;
    for(int i=0;i<x.length()-1;i++)
    {
        if(x[i]=='.'&&x[i+1]=='.')
            counter++;
    }
    while(q--)
    {
        int a;
        char c;
        cin>>a>>c;
        if(c!='.')
        {
            if(a==1)
            {
                if(x[a-1]=='.')
                {
                    if(x[a]=='.')
                        counter--;
                }
                x[a-1]=c;
            }
            else if(a==n)
            {
                if(x[n-1]=='.')
                {
                    if(x[n-2]=='.')
                        counter--;
                }
                x[n-1]=c;
            }
            else
            {
                if(x[a-1]=='.')
                {
                    if(x[a]=='.')
                        counter--;
                    if(x[a-2]=='.')
                        counter--;
                }
                x[a-1]=c;
            }
        }
        else
        {
            if(a==1)
            {
                if(x[a-1]!='.')
                {
                    if(x[a]=='.')
                        counter++;
                }
                x[a-1]=c;
            }
            else if(a==n)
            {
                if(x[n-1]!='.')
                {
                    if(x[n-2]=='.')
                        counter++;
                }
                x[n-1]=c;
            }
            else
            {
                if(x[a-1]!='.')
                {
                    if(x[a]=='.')
                        counter++;
                    if(x[a-2]=='.')
                        counter++;
                }
                x[a-1]=c;
            }
        }
        cout<< counter<<"\n";
    }

}