Submission #571791

#	Time	Username	Problem	Language	Result	Execution time	Memory
571791		Blagojce	PIN (CEOI10_pin)	C++11	0 / 100	5 ms	3532 KiB

pin

#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define st first
#define nd second 
#define all(x) begin(x), end(x)
#define pb push_back
#define all(x) begin(x), end(x)

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;

const int mxn = 1e5+5;
const ll inf = 1e18;
const ld eps = 1e-13;
const ll mod = 1e9 + 9;

mt19937 _rand(time(0));

int n, k;
string s[mxn];
unordered_map<string, int> mapa;

ll ans = 0;
void process(int j){
	fr(mask, 1, (1<<4)){
		int bts = __builtin_popcount(mask);
		if(bts < k) continue;
		string ns = "$$$$";
		fr(i, 0, 4){
			if(mask&(1<<i)){
				ns[i] = s[j][i];
			}
		}
		int p = +1;
		if((bts-k)%2){
			 p = -1;
		}
		ans += mapa[ns]*p;
	}
	fr(mask, 1, (1<<4)){
		string ns = s[j];
		fr(i, 0, 4){
			if(mask&(1<<i)) continue;
			ns[i] = '$';
		}
		mapa[ns] ++;
	}
}


int main(){
	freopen("r.in","r", stdin); 
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cin >> n >> k;
	fr(i, 0, n){
		cin >> s[i];
	
	}
	k = 4-k;
	
	fr(i, 0, n)process(i);
	if(k == 4){
		cout<<ans<<endl;
		return 0;
	}
	
	int ans2 = ans;
	
	
	ans = 0;
	mapa.clear();
	k++;
	fr(i, 0, n)process(i);
	
	cout<<ans2-ans<<endl;
	return 0;
	
}/*
1
3
2 3 -1*/

Compilation message (stderr)

pin.cpp: In function 'int main()':
pin.cpp:54:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |  freopen("r.in","r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100