Submission #757350

#	Time	Username	Problem	Language	Result	Execution time	Memory
757350		drdilyor	Seats (IOI18_seats)	C++17	11 / 100	4083 ms	51600 KiB

seats

#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("unroll-loops")

#include<bits/stdc++.h>
#include "seats.h"
using namespace std;
using ll = long long;
 
int h, w;
std::vector<int> r, c;
vector<vector<int>> arr;
 
struct Fenwick {
    int n, m;
    vector<vector<ll>> t;
    Fenwick() = default;
    Fenwick(int n, int m) : n(n), m(m), t(n, vector<ll>(m)) {}
    ll sum(int r, int c) {
        ll s = 0;
        for (int i = r; i >= 0; i = (i&(i+1))-1)
            for (int j = c; j >= 0; j = (j&(j+1))-1)
                s += t[i][j];
        return s;
    }
    ll sum(int r1, int c1, int r2, int c2) {
        return sum(r2, c2) + sum(r1-1, c1-1) - sum(r1-1, c2) - sum(r2, c1-1);
    }
    void inc(int r, int c, int d) {
        for (; r < n; r |= r+1)
            for (int i = c; i < m; i |= i+1)
                t[r][i] += d;
    }
};
 
Fenwick ft;
 
 
void give_initial_chart(int H, int W, std::vector<int> R, std::vector<int> C) {
    h = H;
    w = W;
    r = R;
    c = C;
    arr = vector(H, vector<int>(W, 0));
    ft = Fenwick(H, W);
    for (int i = 0; i < H * W; i++) {
        arr[r[i]][c[i]] = i;
        ft.inc(r[i], c[i], i);
    }
#ifdef ONPC
    for (int i = 0; i < H; i++)
        for (int j = 0; j < W; j++)
            cout << arr[i][j] << " \n"[j == W-1];
#endif
}
 
int swap_seats(int a, int b) {
    ft.inc(r[a], c[a], -a +b);
    ft.inc(r[b], c[b], -b +a);
    swap(arr[r[a]][c[a]], arr[r[b]][c[b]]);
    swap(r[a], r[b]);
    swap(c[a], c[b]);
    int ans = 1;
    int r1 = r[0], r2 = r[0];
    int c1 = c[0], c2 = c[0];
    int k = 1;
    int steps = 0;
    while (true) {
        r1 = min(r1, r[k]);
        r2 = max(r2, r[k]);
        c1 = min(c1, c[k]);
        c2 = max(c2, c[k]);
        int nk = (r2 - r1 +1) * (c2 - c1 +1);
        if (ft.sum(r1, c1, r2, c2) == (ll)nk * (nk-1) / 2)
            ans++;
        if (nk == h * w) break;
        for (; k < nk; k++) {
            r1 = min(r1, r[k]);
            r2 = max(r2, r[k]);
            c1 = min(c1, c[k]);
            c2 = max(c2, c[k]);
        }
        steps++;
        if (k >= h * w) break;
    }
    assert(steps <= h + w);
    return ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 6 / 6
• Subtask 3: 0 / 20
• Subtask 4: 0 / 6
• Subtask 5: 0 / 33
• Subtask 6: 0 / 30