#include <bits/stdc++.h> #define int long long #define ll long long #define all(x) x.begin(), x.end() #define allr(x) x.rbegin(), x.rend() #define sz size() #define yes "YES" #define no "NO" #define IOI ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0) #define pb push_back #define pf push_front #define mkp make_pair #define S second #define F first using namespace std; void freeopen () { freopen("A.in", "r", stdin); freopen("A.out", "w", stdout); } const int N = 2e5 + 10; const int NN = 1e5 + 5; const int Mod = 1e9 + 7; const ll inf = 1e18; const double pi = 3.14159265358979323846; ll mod (ll x) { return (x % Mod + Mod) % Mod; } ll bp(ll a, int b) { ll res = 1; while(b) { if (b % 2) { res = mod(res * a); } a = mod(a * a); b >>= 1LL; } return res; } ll gcd(ll a, ll b){ while(b) { a %= b; swap(a, b); } return a; } ll lcm(ll a, ll b){ return a / gcd(a, b) * b; } void legenda_ne_umret() { int n, k, ans =0; cin >> n >> k; string s[n]; unordered_map<string, int> cnt; if (k == 4) { for (int i = 0; i < n; i++) { cin >> s[i]; ans += max(0ll, (i) - cnt[s[i]]); cnt[s[i]]++; } cout << ans; return; } for (int i = 0; i < n; i++) { cin >> s[i]; for (int mask = 0; mask < (1 << 4); mask++) { if (__builtin_popcount(mask) != k) continue; string ss = s[i]; for (int bit = 0; bit < 4; bit++) { if ((mask >> bit) & 1) { ss[bit] = '?'; } } ans += cnt[ss]; } for (int mask = 0; mask < (1 << 4); mask++) { if (__builtin_popcount(mask) != k) continue; string ss = s[i]; for (int bit = 0; bit < 4; bit++) { if ((mask >> bit) & 1) { ss[bit] = '?'; } } cnt[ss]++; } } cout << ans; } signed main() { IOI; // freeopen(); /////////////////////////////////////////// int t = 1; // cin >> t; for (int i = 1; i <= t; i++) { // cout << "Case " << i << ": "; legenda_ne_umret(); cout << '\n'; } }

pin.cpp: In function 'void freeopen()':
pin.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     freopen("A.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~
pin.cpp:21:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |     freopen("A.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~