While up solving F — Dasha and Nightmares I came across an unusual error. It's been more than six months now I'm practicing writing #define int long long int pragma at the start of my code, I never faced any issues except today.

I submitted 2 codes, when I write #define int long long int it's giving MLE error but if I removed that line it's getting accepted. I'm using GNU C++20 (64). Although both code are running fine in my sublime text editor.

MLE :

#include <bits/stdc++.h>
#define int long long int

const int MAXN = 26;
int cnt[1 << MAXN];

void solve(){

    std::ios::sync_with_stdio(false);
    std::cin.tie(0);

    int n; 
    std::cin >> n;
 
    std::vector<std::pair <int, int>> vals;

    for (int i = 0; i < n; i++) {
        std::string s; 
        std::cin >> s;
        int cor = 0, cxor = 0;
        for (char c : s) {
            int v = (c - 'a');
            cor = cor | (1 << v);
            cxor = cxor ^ (1 << v);
        }
        vals.push_back({cor, cxor});
    }
 
    int ans = 0;
  
    for (int i = 0; i < 26; i++) {
        int goal = ((1 << 26) - 1) ^ (1 << i);
 
        for (auto [cor, cxor] : vals) {
            if (cor & (1 << i)) continue;
            ans += cnt[cxor ^ goal];
            cnt[cxor] += 1;
        }

        for (auto [cor, cxor] : vals) {
            if (cor & (1 << i)) continue;
            cnt[cxor] -= 1;
        }
    }

    std::cout << ans << "\n";

}
     
signed main() {

    int t = 1;
    //std::cin >> t;
    for(int i = 1; i <= t; i++) {
        solve();
    }
}

AC :

#include <bits/stdc++.h>

const int MAXN = 26;
int cnt[1 << MAXN];

void solve(){

    std::ios::sync_with_stdio(false);
    std::cin.tie(0);

    int n; 
    std::cin >> n;
 
    std::vector<std::pair <int, int>> vals;

    for (int i = 0; i < n; i++) {
        std::string s; 
        std::cin >> s;
        int cor = 0, cxor = 0;
        for (char c : s) {
            int v = (c - 'a');
            cor = cor | (1 << v);
            cxor = cxor ^ (1 << v);
        }
        vals.push_back({cor, cxor});
    }
 
    long long ans = 0;
  
    for (int i = 0; i < 26; i++) {
        int goal = ((1 << 26) - 1) ^ (1 << i);
 
        for (auto [cor, cxor] : vals) {
            if (cor & (1 << i)) continue;
            ans += cnt[cxor ^ goal];
            cnt[cxor] += 1;
        }

        for (auto [cor, cxor] : vals) {
            if (cor & (1 << i)) continue;
            cnt[cxor] -= 1;
        }
    }

    std::cout << ans << "\n";

}
     
signed main() {

    int t = 1;
    //std::cin >> t;
    for(int i = 1; i <= t; i++) {
        solve();
    }
}

Is there any downsides of using #int long long int ? I have seen AwakeAnay using #define int long long int, maybe you can help me ! Also this code I have taken from BucketPotato, can you help ?

What practice should be followed in general so there is not an integer overflow ?

Thank you :)