Submission #980704

#	Time	Username	Problem	Language	Result	Execution time	Memory
980704		vjudge1	Hexagonal Territory (APIO21_hexagon)	C++17	51 / 100	2107 ms	375960 KiB

hexagon

#include "hexagon.h"

#include <bits/stdc++.h>

using namespace std;

const int mod = 1e9 + 7;

long long pw(long long x, long long n) {
    long long res = 1;
    while (n > 0) {
        if (n & 1) {
            res = res * x % mod;
        }
        n /= 2;
        x = x * x % mod;
    }
    return res;
}

const int N = 400400;
const int Q = 200200;

int dx[6] = {-1, -1, 0, 1, 1, 0};
int dy[6] = {-1, 0, 1, 1, 0, -1};
long long X = 0, Y = 0;

vector<int> v[N];
vector<pair<int, int>> g[N];

int G;
int A[N];
int B[N];
int a[N];
int b[N];
int f[N];

long long F(long long x) {
    return x * (x + 1) / 2 % mod;
}

void dfs(int x, int p) {
    Y += 1ll * f[x] * (B[x] - A[x] + 1) % mod;
    Y += F(B[x] - b[x]) + F(a[x] - A[x]);
    for (auto yy: g[x]) {
        int y = yy.first;
        int dir = yy.second;
        if (y == p) {
            continue;
        }
        a[y] = a[x] - 1;
        b[y] = b[x] + 1;
        f[y] = f[x] + 1;

        if (dir == 1) {
            a[y] += 1;
        } else {
            b[y] -= 1;
        }

        if (max(A[y], a[y]) > min(B[y], b[y])) {
            if (b[y] < A[y]) {
                f[y] += A[y] - b[y];
                a[y] = b[y] = A[y];
            } else {
                f[y] += a[y] - B[y];
                a[y] = b[y] = B[y];
            }
        } else {
            a[y] = max(a[y], A[y]);
            b[y] = min(b[y], B[y]);
        }

        dfs(y, x);
    }
}

void work() {
    for (int i = 0; i < N; i++) {
        sort(v[i].begin(), v[i].end());
    }
    vector<int> shit;
    int root = -1;
    for (int i = 0; i < N; i++) {
        assert (v[i].size() % 2 == 0);
        vector<int> cur;
        for (int j = 0; j < v[i].size(); j += 2) {
            int l = v[i][j];
            int r = v[i][j + 1];
            G += 1;

            A[G] = l;
            B[G] = r;
            X += r - l + 1;

            cur.push_back(G);

            if (A[G] <= 0 && 0 <= B[G] && i == Q) {
                root = G;
            }
        }
        for (int j = 0, h = 0; j < cur.size(); j++) {
            while (h < shit.size() && B[shit[h]] < A[cur[j]]) {
                h += 1;
            }
            if (h < shit.size() && A[shit[h]] <= B[cur[j]]) {
                g[shit[h]].push_back({cur[j], 1});
                g[cur[j]].push_back({shit[h], 0});
                while (h + 1 < shit.size() && A[shit[h + 1]] <= B[cur[j]]) {
                    h += 1;
                    g[shit[h]].push_back({cur[j], 1});
                    g[cur[j]].push_back({shit[h], 0});
                }
            }

            /*
            for (int h = 0; h < shit.size(); h++) {
                if (max(A[shit[h]], A[cur[j]]) <= min(B[shit[h]], B[cur[j]])) {
                    g[shit[h]].push_back({cur[j], 1});
                    g[cur[j]].push_back({shit[h], 0});
                }
            }
            */
        }
        swap(cur, shit);
    }

    dfs(root, root);
}

int draw_territory(int N, int A, int B,
                   std::vector<int> D, std::vector<int> L) {


    if (N == 3) {
        assert (L[0] == L[1]);
        assert (L[1] == L[2]);

        long long x = L[0] + 1;
        X = x * (x + 1) / 2;
        Y = x * (x + 1) % mod * (2 * x + 1) % mod * pw(6, mod - 2) - X;
    } else {
        vector<pair<int, int>> p;
        set<pair<int, int>> fucked;

        int x = 0, y = 0;
        for (int i = 0; i < N; i++) {
            int dir = D[i] - 1;
            for (int j = 0; j < L[i]; j++) {
                x += dx[dir];
                y += dy[dir];
                p.push_back({x, y});

                for (int h = 0; h < 6; h++) {
                    fucked.insert({x + dx[h], y + dy[h]});
                }
            }
        }
        for (auto xi: p) {
            fucked.erase(xi);
        }

        set<pair<int, int>> outers;
        queue<pair<int, int>> q;

        q.push(*fucked.begin());
        outers.insert(*fucked.begin());

        while (!q.empty()) {
            int x = q.front().first;
            int y = q.front().second;
            q.pop();
            for (int i = 0; i < 6; i++) {
                int nx = x + dx[i];
                int ny = y + dy[i];
                if (fucked.find({nx, ny}) == fucked.end()) {
                    continue;
                } else if (outers.find({nx, ny}) == outers.end()) {
                    outers.insert({nx, ny});
                    q.push({nx, ny});
                }
            }
        }

        for (auto xi: p) {
            int x = xi.first;
            int y = xi.second;
            if (outers.find({x, y - 1}) != outers.end()) {
                v[x + Q].push_back(y);
            }
            if (outers.find({x, y + 1}) != outers.end()) {
                v[x + Q].push_back(y);
            }
        }

        work();
    }

    X %= mod;
    Y %= mod;

    long long res = X * A % mod + Y * B % mod;

    res = (res % mod + mod) % mod;

    return res;
}

Compilation message (stderr)

hexagon.cpp: In function 'void work()':
hexagon.cpp:87:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |         for (int j = 0; j < v[i].size(); j += 2) {
      |                         ~~^~~~~~~~~~~~~
hexagon.cpp:102:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  102 |         for (int j = 0, h = 0; j < cur.size(); j++) {
      |                                ~~^~~~~~~~~~~~
hexagon.cpp:103:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  103 |             while (h < shit.size() && B[shit[h]] < A[cur[j]]) {
      |                    ~~^~~~~~~~~~~~~
hexagon.cpp:106:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  106 |             if (h < shit.size() && A[shit[h]] <= B[cur[j]]) {
      |                 ~~^~~~~~~~~~~~~
hexagon.cpp:109:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |                 while (h + 1 < shit.size() && A[shit[h + 1]] <= B[cur[j]]) {
      |                        ~~~~~~^~~~~~~~~~~~~

• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 11 / 11
• Subtask 4: 12 / 12
• Subtask 5: 0 / 15
• Subtask 6: 19 / 19
• Subtask 7: 0 / 18
• Subtask 8: 0 / 16