【开源社区openEuler实践】D. Meta-set

题目

思路：

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define fi first
#define se second
#define lson p << 1
#define rson p << 1 | 1
const int maxn = 1e6 + 5, inf = 1e18, maxm = 4e4 + 5;
const int N = sqrt(1e9) + 1;
 const int mod = 1e9 + 7;
// const int mod = 998244353;
//const __int128 mod = 212370440130137957LL;
// int a[505][5005];
// bool vis[505][505];

int a[maxn], b[maxn];
bool vis[maxn];
string s[maxn];
int n, m;

struct Node{
    int val, id;
    bool operator<(const Node &u)const{
        return val < u.val;
    }
};
// Node c[maxn];

int ans[maxn];
int pre[maxn];

//long long ? maxn ? n? m?

string get(string s, string t){
    string res;
    for(int i = 0; i < s.size(); i++){
        if(s[i] == t[i]){
            res += s[i];
        }
        else{
            res += char(3 - (s[i] - '0') - (t[i] - '0') + '0');
        }
    }
    return res;
}

void solve(){
    int res = 0;
    int q, k;
    int x;
    cin >> n >> k;
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= k; j++){
            char ch;
            cin >> ch;
            s[i] += ch;
        }
    }
    map<string, int> mp;
    for(int i = 1; i <= n; i++){
        for(int j = i + 1; j <= n; j++){
            string t = get(s[i], s[j]);
            mp[t]++;
        }
    }
    for(int i = 1; i <= n; i++){
        res += mp[s[i]] * (mp[s[i]] - 1) / 2;
    }
    cout << res << '\n';
}   
    
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);

    int T = 1;
    // cin >> T;
    while (T--)
    {
        solve();
    }
    return 0;
}