Submission #374975

#	Time	Username	Problem	Language	Result	Execution time	Memory
374975		_martynas	Cards (LMIO19_korteles)	C++11	100 / 100	88 ms	6744 KiB

korteles

#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const int MAX_N = 26*26*26*26 + 5;

int n;

char C[MAX_N][4]; // cards
int cnt[MAX_N];
int L[676], R[676], U[676], D[676];

void Read(char IN[])
{
    scanf(" %c%c %c%c", &IN[0], &IN[1], &IN[2], &IN[3]);
}

int Hash2(char a, char b)
{
    return 26 * (a - 'A') + (b - 'A');
}

int Hash4(char Arr[4])
{
    int h = 0;
    for(int i = 0; i < 4; i++)
    {
        h *= 26;
        h += Arr[i] - 'A';
    }
    return h;
}

int Hash4(int a, int b, int c, int d)
{
    int h = a;
    h *= 26;
    h += b;
    h *= 26;
    h += c;
    h *= 26;
    h += d;
    return h;
}

int main()
{
    scanf("%d", &n);

    ll ans = 0;

    for(int i = 0; i < n; i++)
    {
        Read(C[i]);
        L[Hash2(C[i][0], C[i][2])]++;
        R[Hash2(C[i][1], C[i][3])]++;
        U[Hash2(C[i][0], C[i][1])]++;
        D[Hash2(C[i][2], C[i][3])]++;
        cnt[Hash4(C[i])]++;
        //cout << C[i] << endl;
        if(C[i][0] == C[i][2] && C[i][1] == C[i][3]) // counts himself
        {
            ans--;
        }
        if(C[i][0] == C[i][1] && C[i][2] == C[i][3]) // counts himself
        {
            ans--;
        }
    }

    for(int i = 0; i <= 676; i++)
    {
        ans += (ll)L[i] * R[i];
        ans += (ll)U[i] * D[i];
    }

    for(int i = 0; i < 26; i++) for(int j = 0; j < 26; j++)
    {
        for(int k = 0; k < 26; k++) for(int l = 0; l < 26; l++)
        {
            int h1, h2;
            h1 = Hash4(i, j, k, l);
            h2 = Hash4(k, l, i, j);

            /*
            IJ KL
            KL IJ
            */

            if(h1 < h2)
                ans -= cnt[h1] * cnt[h2];

            h2 = Hash4(j, i, l, k);

            /*
            IJ JI
            KL LK
            */

            if(h1 < h2)
                ans -= cnt[h1] * cnt[h2];

            h1 = Hash4(i, j, k, i), h2 = Hash4(j, l, i, j);

            /*
            IJ JL
            KI IJ
            */

            if(h1 != h2)
                ans -= cnt[h1] * cnt[h2];

            h1 = Hash4(k, i, i, j), h2 = Hash4(i, j, j, l);

            /*
            KI IJ
            IJ JL
            */

            if(h1 != h2)
                ans -= cnt[h1] * cnt[h2];

        }
        /*
        IJ JI
        JI IJ
        */
        if(i < j)
        {
            ans += 3 * cnt[Hash4(i, j, j, i)] * cnt[Hash4(j, i, i, j)];
        }
    }

    cout << ans << endl;

    return 0;
}
/* INPUT
3
IO
OI
AA
AA
OI
IO
*/

Compilation message (stderr)

korteles.cpp: In function 'void Read(char*)':
korteles.cpp:17:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   17 |     scanf(" %c%c %c%c", &IN[0], &IN[1], &IN[2], &IN[3]);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
korteles.cpp: In function 'int main()':
korteles.cpp:50:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   50 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
korteles.cpp:75:23: warning: iteration 676 invokes undefined behavior [-Waggressive-loop-optimizations]
   75 |         ans += (ll)L[i] * R[i];
      |                    ~~~^
korteles.cpp:73:22: note: within this loop
   73 |     for(int i = 0; i <= 676; i++)
      |                    ~~^~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 19 / 19
• Subtask 5: 25 / 25