Submission #951367

#	Time	Username	Problem	Language	Result	Execution time	Memory
951367		Nhoksocqt1	Hexagonal Territory (APIO21_hexagon)	C++17	47 / 100	709 ms	49008 KiB

hexagon

#include<bits/stdc++.h>
using namespace std;

#define inf 0x3f3f3f3f
#define sz(x) int((x).size())
#define fi first
#define se second
typedef long long ll;
typedef pair<int, int> ii;

template<class X, class Y>
	inline bool maximize(X &x, const Y &y) {return (x < y ? x = y, 1 : 0);}
template<class X, class Y>
	inline bool minimize(X &x, const Y &y) {return (x > y ? x = y, 1 : 0);}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int Random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

const int MAXN = 200005;
const int MOD = 1e9+7;

const int lx[] = {0, 1, 1, 0, -1, -1};
const int ly[] = {2, 1, -1, -2, -1, 1};

struct Move {
    int dir, len;
} p[MAXN];

ll costA, costB;
int dist[4010][8010], numMove;
bool dx[4010][8010], dxr[4010][8010];

inline ll C2(int n) {
    return 1LL * n * (n + 1) / 2 % MOD;
}

ll powermod(ll a, int exponent) {
    ll res(1);
    while(exponent > 0) {
        if(exponent & 1)
            res = res * a % MOD;

        a = a * a % MOD;
        exponent >>= 1;
    }

    return res;
}

int inv6 = powermod(6, MOD - 2);
inline ll T2(int n) {
    return 1LL * n * (n + 1) % MOD * (2 * n + 1) % MOD * inv6 % MOD;
}

int subn3(void) {
    assert(p[1].len == p[2].len && p[2].len == p[3].len);
    assert(p[2].dir == (p[1].dir + 1) % 6 + 1 && p[3].dir == (p[2].dir + 1) % 6 + 1 || p[1].dir == (p[2].dir + 1) % 6 + 1 && p[2].dir == (p[3].dir + 1) % 6 + 1);

    ll ans = C2(p[1].len + 1) * costA % MOD;
    ans = (ans - C2(p[1].len + 1) * costB % MOD + MOD) % MOD;
    ans = (ans + T2(p[1].len + 1) * costB) % MOD;
    return ans;
}

int sub3(void) {
    int x(2001), y(4002);
    dx[x][y] = 1;

    //cout << x - 2001 << ' '<< y - 4002 << '\n';
    for (int i = 1; i <= numMove; ++i) {
        int len(p[i].len), dir(p[i].dir - 1);
        while(len--) {
            x += lx[dir], y += ly[dir];
            dx[x][y] = 1;
        }

        //cout << x - 2001 << ' '<< y - 4002 << '\n';
    }

    queue<ii> qu;
    qu.push(ii(2001, 0));
    dxr[2001][0] = 1;

    while(sz(qu)) {
        int x(qu.front().fi), y(qu.front().se);
        qu.pop();

        for (int id = 0; id < 6; ++id) {
            int u(x + lx[id]), v(y + ly[id]);
            if(min(u, v) < 0 || u > 4002 || v > 8004 || dx[u][v] || dxr[u][v])
                continue;

            dxr[u][v] = 1;
            qu.push(ii(u, v));
        }
    }

    qu.push(ii(x, y));
    dist[x][y] = 1;

    while(sz(qu)) {
        int x(qu.front().fi), y(qu.front().se);
        qu.pop();

        for (int id = 0; id < 6; ++id) {
            int u(x + lx[id]), v(y + ly[id]);
            if(min(u, v) < 0 || u > 4002 || v > 8004 || dist[u][v] > 0 || dxr[u][v])
                continue;

            dist[u][v] = dist[x][y] + 1;
            qu.push(ii(u, v));
        }
    }

    ll res(0);
    int cntNodes(0);
    for (int i = 0; i <= 4002; ++i) {
        for (int j = 0; j <= 8004; ++j) {
            if(dist[i][j] > 0) {
                res = (res + (dist[i][j] - 1) * costB + costA) % MOD;
                ++cntNodes;
            }
        }
    }

    //cout << '.' << cntNodes << '\n';
    return res;
}

struct Point {
    int x, y;

    Point(int _x = 0, int _y = 0) : x(_x), y(_y) {};
} point[MAXN];

int subB0(void) {
    ll S(0), B(0);
    int x(0), y(0);
    point[0] = Point(x, y);
    for (int i = 1; i <= numMove; ++i) {
        int len(p[i].len), dir(p[i].dir - 1);
        x += lx[dir] * len;
        y += ly[dir] * len;
        point[i] = Point(x, y);
        B += len;
    }

    for (int i = 0; i < numMove; ++i)
        S += (1LL * point[i].x * point[i + 1].y - 1LL * point[i].y * point[i + 1].x);

    S = abs(S);
    //cout << S << ' ' << S / 2 << ' ' << B << ' ' << ((S / 4 - B) / 2 + B + 1) << '\n';
    return ((S / 2 - B) / 2 + B + 1) % MOD * costA % MOD;
}

int draw_territory(int _N, int _A, int _B, vector<int> _D, vector<int> _L) {
    numMove = _N, costA = _A, costB = _B;

    int sumLen(0);
    for (int i = 1; i <= numMove; ++i) {
        p[i] = {_D[i - 1], _L[i - 1]};
        sumLen += p[i].len;
    }

    if(numMove == 3)
        return subn3();

    if(sumLen <= 2000)
        return sub3();

    //cout << "        " << sub3() << '\n';
    if(costB == 0)
        return subB0();
}

#ifdef Nhoksocqt1

int main(void) {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    #define TASK "hexagon"
    if(fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    vector<int> d, l;
    int n, a, b;
    cin >> n >> a >> b;

    d.resize(n), l.resize(n);
    for (int i = 0; i < n; ++i)
        cin >> d[i] >> l[i];

    int answer = draw_territory(n, a, b, d, l);
    cout << "ANSWER: " << answer << '\n';

    return 0;
}

#endif // Nhoksocqt1

Compilation message (stderr)

In file included from /usr/include/c++/10/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:33,
                 from hexagon.cpp:1:
hexagon.cpp: In function 'int subn3()':
hexagon.cpp:59:47: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   59 |     assert(p[2].dir == (p[1].dir + 1) % 6 + 1 && p[3].dir == (p[2].dir + 1) % 6 + 1 || p[1].dir == (p[2].dir + 1) % 6 + 1 && p[2].dir == (p[3].dir + 1) % 6 + 1);
      |            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hexagon.cpp: In function 'int draw_territory(int, int, int, std::vector<int>, std::vector<int>)':
hexagon.cpp:176:1: warning: control reaches end of non-void function [-Wreturn-type]
  176 | }
      | ^

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