Submission #498927

#	Time	Username	Problem	Language	Result	Execution time	Memory
498927		Victor	Sateliti (COCI20_satellti)	C++17	50 / 110	3068 ms	34628 KiB

Main

// #pragma GCC target ("avx,avx2,fma")
// #pragma GCC optimize ("Ofast,inline") // O1 - O2 - O3 - Os - Ofast
// #pragma GCC optimize ("unroll-loops")
#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define per(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define trav(a, x) for (auto &a : x)

#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define debug(x) cout << #x << " = " << x << endl

#define umap unordered_map
#define uset unordered_set

typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;

typedef long long ll;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;

const int INF = 1'000'000'007;

const ll modulo[] = {INF, INF + 2}, bases[] = {1337, 4269}, num_bases = 2;
string grid[1001];
int rows, cols;
ll base_pow[num_bases][2001], prefix_hash[1001][2001][num_bases];

int hash_val(int row, int len, int base, int start) { return ((prefix_hash[row][start + len - 1][base] - (start ? prefix_hash[row][start - 1][base] : 0) * base_pow[base][len]) % modulo[base] + modulo[base]) % modulo[base]; }

int start = 0, s1, s2, len;
bool prank;
int order[1001], vals[2001];
bool cmp(const int &a, const int &b) {
    int lo = 0, hi = len;
    while (lo != hi) {
        int mid = (lo + hi) / 2;
        bool differ = 0;
        rep(base, 0, num_bases) differ |= hash_val(a, mid + 1, base, s1) != hash_val(b, mid + 1, base, s2);

        // if (prank) cout << "lo = "<<lo<<" hi = "<<hi<<" differ = "<<differ<<endl;
        if (differ)
            hi = mid;
        else
            lo = mid + 1;
    }

    if (prank) {
        //cout << "pos = " << lo << " vals = " << vals[s1 + lo] << ' ' << vals[s2 + lo] << ' ' << hash_val(a, 1, 0, s1) << ' ' << hash_val(b, 1, 0, s2) << endl;
        //cout<<prefix_hash[a][s1 + len - 1][0]<<' '<<(s1 ? prefix_hash[a][s1 - 1][0] : 0)<<endl;
        return vals[s1 + lo] < vals[s2 + lo];

    } else
        return grid[a][s1 + lo] < grid[b][s2 + lo];
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    rep(i, 0, num_bases) {
        base_pow[i][0] = 1;
        rep(j, 1, 2001) base_pow[i][j] = base_pow[i][j - 1] * bases[i] % modulo[i];
    }

    cin >> rows >> cols;
    rep(row, 0, rows) {
        cin >> grid[row];
        grid[row].append(grid[row]);
        rep(col, 0, cols * 2) rep(base, 0, num_bases) prefix_hash[row][col][base] = ((col ? prefix_hash[row][col - 1][base] : 0) * bases[base] + grid[row][col]) % modulo[base];
    }

    rep(i, 0, rows) order[i] = i;

    int best_start = -1, best_start_row;
    // cout << endl;
    while (start < cols) {
        s1 = s2 = start;
        len = cols;
        prank = 0;
        sort(order, order + rows, cmp);
        //rep(i, 0, rows) cout << "row = " << order[i] << ' ' << grid[order[i]].substr(start, cols) << endl;
        int pos = 0;
        rep(row, 0, rows) {
            if (row) {
                bool differ = 0;
                rep(base, 0, num_bases) differ |= hash_val(order[row], cols, base, start) != hash_val(order[row - 1], cols, base, start);
                pos += differ;
            }
            vals[order[row]] = vals[order[row] + rows] = pos;
        }

        rep(row, 0, rows * 2) rep(base, 0, num_bases) prefix_hash[rows][row][base] = ((row ? prefix_hash[rows][row - 1][base] : 0) * bases[base] + vals[row % rows]) % modulo[base];

        prank = 1;
        len = rows;
        int cb_start = 0;
        rep(row, 0, rows) {
            s1 = cb_start;
            s2 = row;
            //cout << "s1 = " << s1 << " s2 = " << s2 << endl;
            if (!cmp(rows, rows)) cb_start = row;
        }

        //rep(row, 0, rows * 2) cout << vals[row] << ' ';
        //cout << endl;
        //cout << "shift row = " << cb_start << " shift col = " << start << endl
        //     << endl;

        if (best_start == -1) {
            best_start = start;
            best_start_row = cb_start;

        } else {
            // cout << "best_start = " << best_start << " best_start_row = " << best_start_row << endl;
            // cout << "cur_start = " << start << " cur_start_row = " << cb_start << endl;

            prank = 0;
            len = cols;
            rep(row, 0, rows) {
                int a = (best_start_row + row) % rows;
                int b = (cb_start + row) % rows;
                // cout<<"a = "<<a<<" b = "<<b<<endl;
                s1 = best_start;
                s2 = start;

                bool differ = 0;
                rep(base, 0, num_bases) differ |= hash_val(a, len, base, s1) != hash_val(b, len, base, s2);
                if (differ) {
                    if (!cmp(a, b)) {
                        best_start = start;
                        best_start_row = cb_start;
                    }
                    break;
                }
            }
        }
        // cout << endl;
        ++start;
    }

    cout << endl;
    rep(i, 0, rows) {
        rep(j, 0, cols) cout << grid[(i + best_start_row) % rows][(j + best_start) % cols];
        cout << endl;
    }
    //cout << best_start_row << ' ' << best_start << endl;
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:84:26: warning: 'best_start_row' may be used uninitialized in this function [-Wmaybe-uninitialized]
   84 |     int best_start = -1, best_start_row;
      |                          ^~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 40 / 40
• Subtask 3: 0 / 60