Submission #466730

#	Time	Username	Problem	Language	Result	Execution time	Memory
466730		rainboy	Hexagonal Territory (APIO21_hexagon)	C++17	66 / 100	738 ms	30252 KiB

hexagon

#include "hexagon.h"
#include <stdlib.h>
#include <vector>

using namespace std;

typedef vector<int> vi;

const int N = 200000, MD = 1000000007, V2 = 500000004, V6 = 166666668;

int min(int a, int b) { return a < b ? a : b; }
int max(int a, int b) { return a > b ? a : b; }

unsigned int X = 12345;

int rand_() {
	return (X *= 3) >> 1;
}

int dx[] = { 1, 1, 0, -1, -1, 0 };
int dy[] = { 0, 1, 1, 0, -1, -1 };

int choose2(int n) {
	return (long long) n * (n - 1) % MD * V2 % MD;
}

int choose3(int n) {
	return (long long) n * (n - 1) % MD * (n - 2) % MD * V6 % MD;
}

long long cross(int x1, int y1, int x2, int y2) {
	return (long long) x1 * y2 - (long long) x2 * y1;
}

int hh[N], ll[N], ii[N], xx[N][2], yy[N], n, n_;

void add(int x1, int y1, int x2, int y2) {
	if (y1 < y2)
		xx[n_][0] = x1, xx[n_][1] = x2, yy[n_] = y1, n_++;
	else if (y1 > y2)
		xx[n_][0] = x2, xx[n_][1] = x1, yy[n_] = y2, n_++;
}

void sort(int *ii, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;

		while (j < k) {
			int c = yy[ii[j]] != yy[i_] ? yy[ii[j]] - yy[i_] : (xx[ii[j]][0] + xx[ii[j]][1]) - (xx[i_][0] + xx[i_][1]);

			if (c == 0)
				j++;
			else if (c < 0) {
				tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
			}
		}
		sort(ii, l, i);
		l = k;
	}
}

int *ej[N], eo[N];

void append(int i, int j) {
	int o = eo[i]++;

	if (o >= 2 && (o & o - 1) == 0)
		ej[i] = (int *) realloc(ej[i], o * 2 * sizeof *ej[i]);
	ej[i][o] = j;
}

int dfs(int p, int i, int d) {
	int i_ = i >> 1, s = i & 1, o, x;

	x = (long long) d * (xx[ii[i_ << 1 | 1]][s] - xx[ii[i_ << 1 | 0]][s] + 1) % MD;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			if ((i ^ j) == 1)
				x = (x + dfs(i, j, d + 1)) % MD; 
			else {
				int j_ = j >> 1, t = j & 1;

				x = (x + dfs(i, j, d)) % MD;
				x = (x - (long long) d * (min(xx[ii[j_ << 1 | 1]][t], xx[ii[i_ << 1 | 1]][s]) - max(xx[ii[j_ << 1 | 0]][t], xx[ii[i_ << 1 | 0]][s]) + 1)) % MD;
			}
		}
	}
	return x;
}

int solve() {
	int h, i, j, k, l, x, y, ans;

	n_ = 0, x = 0, y = 0;
	for (i = 0; i < n; i++)
		for (l = 0; l < ll[i]; l++)
			add(x, y, x + dx[hh[i]], y + dy[hh[i]]), x += dx[hh[i]], y += dy[hh[i]];
	for (i = 0; i < n_; i++)
		ii[i] = i;
	sort(ii, 0, n_);
	n_ /= 2;
	for (i = 0; i < n_ * 2; i++)
		ej[i] = (int *) malloc(2 * sizeof *ej[i]), eo[i] = 0;
	for (i = 0; i < n_; i++)
		append(i << 1 | 0, i << 1 | 1), append(i << 1 | 1, i << 1 | 0);
	for (h = -1, i = 0; i < n_; h = i, i = j) {
		int y = yy[ii[i << 1 | 0]];

		j = i + 1;
		while (j < n_ && yy[ii[j << 1 | 0]] == y)
			j++;
		if (h != -1) {
			k = h, l = i;
			while (k < i && l < j)
				if (xx[ii[k << 1 | 1]][1] < xx[ii[l << 1 | 1]][0]) {
					if (xx[ii[l << 1 | 0]][0] <= xx[ii[k << 1 | 1]][1])
						append(k << 1 | 1, l << 1 | 0), append(l << 1 | 0, k << 1 | 1);
					k++;
				} else {
					if (xx[ii[k << 1 | 0]][1] <= xx[ii[l << 1 | 1]][0])
						append(k << 1 | 1, l << 1 | 0), append(l << 1 | 0, k << 1 | 1);
					l++;
				}
		}
	}
	ans = 0;
	for (i = 0; i < n_; i++) {
		int i0 = ii[i << 1 | 0], i1 = ii[i << 1 | 1];

		if (yy[i0] == 0 && xx[i0][0] <= 0 && 0 <= xx[i1][0]) {
			ans = dfs(-1, i << 1 | 0, 0);
			for (i = 0; i < n_ * 2; i++)
				free(ej[i]);
			break;
		}
		if (yy[i1] + 1 == 0 && xx[i0][1] <= 0 && 0 <= xx[i1][1]) {
			ans = dfs(-1, i << 1 | 1, 0);
			for (i = 0; i < n_ * 2; i++)
				free(ej[i]);
			break;
		}
	}
	return ans;
}

int draw_territory(int n_, int a, int b, vi hh_, vi ll_) {
	int h, i, x, y, ans1, ans2;
	long long area2, boundary, internal;

	n = n_;
	for (i = 0; i < n; i++)
		hh[i] = hh_[i] - 1, ll[i] = ll_[i];
	x = 0, y = 0, area2 = 0, boundary = 0;
	for (i = 0; i < n; i++) {
		h = hh[i];
		area2 += cross(x, y, x + dx[h] * ll[i], y + dy[h] * ll[i]);
		boundary += ll[i];
		x += dx[h] * ll[i], y += dy[h] * ll[i];
	}
	if (area2 < 0)
		area2 = -area2;
	internal = (area2 - boundary) / 2 + 1;
	ans1 = (boundary + internal) % MD, ans2 = 0;
	if (n == 3)
		ans2 = choose3(ll[0] + 2) * 2 % MD;
	else if (b > 0) {
		ans2 = 0;
		for (h = 0; h < 3; h++) {
			ans2 = (ans2 + solve()) % MD;
			for (i = 0; i < n; i++)
				hh[i] = (hh[i] + 1) % 6;
		}
		if (ans2 < 0)
			ans2 += MD;
		ans2 = (long long) ans2 * V2 % MD;
	}
	return ((long long) ans1 * a + (long long) ans2 * b) % MD;
}

Compilation message (stderr)

hexagon.cpp: In function 'void append(int, int)':
hexagon.cpp:71:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   71 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~

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