Submission #758500

#	Time	Username	Problem	Language	Result	Execution time	Memory
758500		drdilyor	Seats (IOI18_seats)	C++17	0 / 100	366 ms	56256 KiB

seats

#include<bits/stdc++.h>
#include "seats.h"
using namespace std;
using ll = long long;
const int inf = 1e9;
 
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;

int nextPower2(int n) {
    n--;
    n |= n >> 1;
    n |= n >> 2;
    n |= n >> 4;
    n |= n >> 8;
    n |= n >> 16;
    return 1+n;
}


struct SegmentTree {
    using S = int;
    struct T {
        int sum=0;
        int min=0;
        int minc=0;
    };
    const T id = {};
    inline T single(S v) { return {v, v, 1}; }

    static T merge(const T& l, const T& r) {
        if (l.min == l.sum + r.min) {
            return {.sum = l.sum + r.sum, .min = l.min, .minc = l.minc + r.minc};
        }
        else if (l.min < l.sum + r.min) {
            return {.sum = l.sum + r.sum, .min = l.min, .minc = l.minc};
        } else {
            return {.sum = l.sum + r.sum, .min = l.sum + r.min, .minc = r.minc};
        }
    }

    int n;
    vector<T> tree;

    SegmentTree() {}
    void init(int n) {
        this->n = n = nextPower2(n);
        tree.assign(n * 2, id);
        build();
    }

    void build() {
        for (int i = n-1; i >= 1; i--) {
            tree[i] = merge(tree[i*2], tree[i*2 + 1]);
        }
    }

    void update(int i, S v) {
        tree[i+=n] = single(v);
        for (i /= 2; i >= 1; i/= 2)
            tree[i] = merge(tree[i*2], tree[i*2+1]);
    }

    int query() {
        return tree[1].minc;
    }
};

 
SegmentTree pot;
 
int add(int i) {
    if (i == 0) return 0;
    auto& brr = arr[0];
    int j = c[i];
    int cnt = 0;
    if (j == 0 || brr[j-1] > i) cnt++;
    else cnt--;
    if (j == w -1 || brr[j+1] > i) cnt++;
    else cnt--;
    return cnt;
};

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);
    }
    pot.init(w);

    for (int i = 0; i < w; i++) {
        pot.update(i, add(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]);

    for (int i : {a-1, a, a+1, b-1, b, b+1}) {
        if (0 <= i && i <= w-1)
            pot.update(i, add(i));
    }

    assert(h == 1);
    int ans = pot.query();
    return ans;
}

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