1921B - Arranging Cats - CodeForces Solution

#include<bits/stdc++.h>
#define ll long long
#define F first
#define no cout<<"NO"<<endl;
#define yes cout<<"YES"<<endl;
#define S second
#define all(x) x.begin(),x.end()
#define pb push_back
#define FAST ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define T int t; cin>>t; while(t--)
#define int ll
using namespace std;
const int N = 4e5+18,MOD=1e9+7;
int dx[] = {0,0,1,-1};
int dy[] = {1,-1,0,0};
ll gcd(ll a,ll b)
{
    if(b==0)return a;
    return gcd(b,a%b);
}
ll lcm(ll a, ll b)
{
    return (a*b)/gcd(a,b);
}
ll power(ll x,ll y)
{
    if(y==0) return 1;
    ll ww=power(x,y/2);
    if(y&1) return ww*ww*x;
    return ww*ww;
}
void solve()
{
    int n;
    string s,d;
    cin>>n>>s>>d;
    int a1=0,a2=0,a3=0;
    for(int i=0;i<n;i++)
    {
        if(s[i]==d[i])
        continue;
        if(s[i]=='1') a1++;
        if(s[i]=='0'&&d[i]=='1')
            a2++;
    }
    cout<<max(a1,a2)<<endl;
}
int32_t main()
{
    FAST;
   T
    solve();
}