Submission #405161

#	Time	Username	Problem	Language	Result	Execution time	Memory
405161		rainboy	Roller Coaster Railroad (IOI16_railroad)	C11	64 / 100	163 ms	9672 KiB

railroad

#include "railroad_c.h"
#include <string.h>

#define N	200001
#define SMALL	16
#define INF	0x3f3f3f3f
#define LINF	0x3f3f3f3f3f3f3f3f

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

unsigned int X = 12345;

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

int xx[N * 2];

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 = xx[ii[j]] != xx[i_] ? xx[ii[j]] - xx[i_] : (ii[j] & 1) - (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 ds[N];

int find(int i) {
	return ds[i] < 0 ? i : (ds[i] = find(ds[i]));
}

void join(int i, int j) {
	i = find(i);
	j = find(j);
	if (i == j)
		return;
	if (ds[i] > ds[j])
		ds[i] = j;
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i;
	}
}

long long plan_roller_coaster(int n, int *aa, int *bb) {
	if (n <= SMALL) {
		static long long dp[1 << SMALL][SMALL];
		int i, j, b;
		long long x;

		for (b = 1; b < 1 << n; b++)
			memset(dp[b], 0x3f, n * sizeof *dp[b]);
		for (i = 0; i < n; i++)
			dp[1 << i][i] = 0;
		for (b = 1; b < 1 << n; b++)
			for (i = 0; i < n; i++) {
				x = dp[b][i];
				if (x == LINF)
					continue;
				for (j = 0; j < n; j++)
					if ((b & 1 << j) == 0)
						dp[b | 1 << j][j] = min(dp[b | 1 << j][j], x + max(bb[i] - aa[j], 0));
			}
		x = LINF;
		for (i = 0; i < n; i++)
			x = min(x, dp[(1 << n) - 1][i]);
		return x;
	} else {
		static int ii[N * 2];
		int i, d;

		for (i = 0; i < n; i++)
			xx[i << 1 | 0] = bb[i], xx[i << 1 | 1] = aa[i];
		xx[n << 1 | 0] = 0, xx[n << 1 | 1] = INF;
		n++;
		for (i = 0; i < n * 2; i++)
			ii[i] = i;
		sort(ii, 0, n * 2);
		memset(ds, -1, n * sizeof *ds);
		for (i = 0, d = 0; i < n * 2; i++) {
			int i_ = ii[i];

			d += (i_ & 1) == 0 ? 1 : -1;
			if (d < 0)
				return 1;
			if (d != 0 && i + 1 < n * 2)
				join(i_ >> 1, ii[i + 1] >> 1);
		}
		for (i = 0; i < n; i++)
			if (find(i) != find(0))
				return 1;
		return 0;
	}
}

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 30 / 30
• Subtask 4: 0 / 36