Submission #445856

#	Time	Username	Problem	Language	Result	Execution time	Memory
445856		rainboy	Sky Walking (IOI19_walk)	C++14	57 / 100	554 ms	280500 KiB

walk

#include "walk.h"
#include <stdlib.h>
#include <string.h>

using namespace std;

typedef vector<int> vi;

const int N = 100000, M = 100000, N_ = 1 << 18, N1 = 4000000, M_ = 4000000;	/* N_ = pow2(ceil(log2(N))) */
const long long INF = 0x3f3f3f3f3f3f3f3f;

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

unsigned int X = 12345;

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

int ii[N], hh[M * 2];

int *aa;

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)
			if (aa[ii[j]] == aa[i_])
				j++;
			else if (aa[ii[j]] < aa[i_]) {
				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 ij[M_], ww[M_], m_;
int *eh[N1], eo[N1], n_;

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

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

int newnode() {
	eh[n_] = (int *) malloc(2 * sizeof *eh[n_]);
	return n_++;
}

void add(int i, int j, int w) {
	int h = m_++;

	ij[h] = i ^ j, ww[h] = w;
	append(i, h), append(j, h);
}

int pp[N], qq[N], top[N], yy1[N];

void push(int i, int y) {
	int t = newnode();

	add(top[i], t, y - yy1[i]);
	top[i] = t, yy1[i] = y;
}

long long dd[N1]; int pq[N1], iq[1 + N1], cnt;

int lt(int i, int j) {
	return dd[i] < dd[j];
}

int p2(int p) {
	return (p *= 2) > cnt ? 0 : (p < cnt && lt(iq[p + 1], iq[p]) ? p + 1 : p);
}

void pq_up(int i) {
	int p, q, j;

	for (p = pq[i]; (q = p / 2) && lt(i, j = iq[q]); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}

void pq_dn(int i) {
	int p, q, j;

	for (p = pq[i]; (q = p2(p)) && lt(j = iq[q], i); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}

void pq_add_last(int i) {
	iq[pq[i] = ++cnt] = i;
}

int pq_remove_first() {
	int i = iq[1], j = iq[cnt--];

	if (j != i)
		pq[j] = 1, pq_dn(j);
	pq[i] = 0;
	return i;
}

long long dijkstra(int s, int t) {
	memset(dd, 0x3f, n_ * sizeof *dd);
	dd[s] = 0, pq_add_last(s);
	while (cnt) {
		int i = pq_remove_first(), o;

		if (i == t)
			return dd[i];
		for (o = eo[i]; o--; ) {
			int h = eh[i][o], j = i ^ ij[h];
			long long d = dd[i] + ww[h];

			if (dd[j] > d) {
				if (dd[j] == INF)
					pq_add_last(j);
				dd[j] = d, pq_up(j);
			}
		}
	}
	return -1;
}

int xx[N], yy[N], ll[M], rr[M], xx1[M * 2], zz[M], idx[M], zz1[M];

long long solve_using_dijkstra(vi xx_, vi yy_, vi ll_, vi rr_, vi zz_, int s, int t) {
	int n = xx_.size(), m = zz_.size(), h, i;

	for (i = 0; i < n; i++) {
		xx[i] = xx_[i], yy[i] = yy_[i];
		ii[i] = i;
	}
	aa = yy, sort(ii, 0, n);
	for (h = 0; h < m; h++) {
		ll[h] = ll_[h], rr[h] = rr_[h], zz[h] = zz_[h];
		hh[h] = h;
	}
	aa = zz, sort(hh, 0, m);
	for (i = 0; i < n; i++) {
		pp[i] = i - 1, qq[i] = i + 1;
		top[i] = newnode(), yy1[i] = 0;
	}
	for (h = 0, i = 0; h < m; h++) {
		int h_ = hh[h], i_;

		while (i < n && yy[i_ = ii[i]] < zz[h_]) {
			if (pp[i_] != -1)
				qq[pp[i_]] = qq[i_];
			if (qq[i_] != n)
				pp[qq[i_]] = pp[i_];
			i++;
		}
		for (i_ = ll[h_]; i_ != rr[h_]; i_ = qq[i_])
			push(i_, zz[h_]);
		push(i_, zz[h_]);
		for (i_ = ll[h_]; i_ != rr[h_]; i_ = qq[i_])
			add(top[i_], top[qq[i_]], xx[qq[i_]] - xx[i_]);
	}
	for (i = 0; i < n; i++)
		push(i, yy[i]);
	return dijkstra(s, t);
}

long long st1[N_ * 2], st2[N_ * 2];

void pul(int i) {
	int l = i << 1, r = l | 1;

	st1[i] = min(st1[l], st1[r]), st2[i] = min(st2[l], st2[r]);
}

void update(int i, long long x) {
	if (x == INF)
		st1[n_ + i] = st2[n_ + i] = INF;
	else
		st1[n_ + i] = x - zz1[i], st2[n_ + i] = x + zz1[i];
	i += n_;
	while (i > 1)
		pul(i >>= 1);
}

long long query(int i) {
	long long x, y;
	int l, r;

	x = INF;
	for (l = 0 + n_, r = i + n_; l <= r; l >>= 1, r >>= 1) {
		if ((l & 1) == 1)
			x = min(x, st1[l++]);
		if ((r & 1) == 0)
			x = min(x, st1[r--]);
	}
	y = INF;
	for (l = i + n_, r = n_ - 1 + n_; l <= r; l >>= 1, r >>= 1) {
		if ((l & 1) == 1)
			y = min(y, st2[l++]);
		if ((r & 1) == 0)
			y = min(y, st2[r--]);
	}
	return min(x == INF ? INF : x + zz1[i], y == INF ? INF : y - zz1[i]);
}

long long dp[M];

long long solve_using_segtree(vi xx_, vi ll_, vi rr_, vi zz_) {
	long long ans;
	int n = xx_.size(), m = zz_.size(), h, i;

	for (i = 0; i < n; i++)
		xx[i] = xx_[i];
	for (h = 0; h < m; h++) {
		ll[h] = ll_[h], rr[h] = rr_[h], zz[h] = zz_[h];
		hh[h] = h;
	}
	aa = zz, sort(hh, 0, m);
	for (h = 0; h < m; h++)
		idx[hh[h]] = h, zz1[h] = zz[hh[h]];
	for (h = 0; h < m * 2; h++) {
		xx1[h] = (h & 1) == 0 ? ll[h >> 1] << 1 | 0 : rr[h >> 1] << 1 | 1;
		hh[h] = h;
	}
	aa = xx1, sort(hh, 0, m * 2);
	n_ = 1;
	while (n_ < m)
		n_ <<= 1;
	memset(st1, 0x3f, n_ * 2 * sizeof *st1), memset(st2, 0x3f, n_ * 2 * sizeof *st2);
	ans = INF;
	for (h = 0; h < m * 2; h++) {
		int h_ = hh[h] >> 1;

		if ((hh[h] & 1) == 0)
			dp[h_] = xx1[hh[h]] == 0 ? zz[h_] : query(idx[h_]), update(idx[h_], dp[h_]);
		else {
			update(idx[h_], INF);
			if (xx1[hh[h]] == (n - 1 << 1 | 1))
				ans = min(ans, dp[h_] + zz[h_] + xx[n - 1] - xx[0]);
		}
	}
	return ans == INF ? -1 : ans;
}

long long min_distance(vi xx_, vi yy_, vi ll_, vi rr_, vi zz_, int s, int t) {
	int n = xx_.size();

	return s == 0 && t == n - 1 ? solve_using_segtree(xx_, ll_, rr_, zz_) : solve_using_dijkstra(xx_, yy_, ll_, rr_, zz_, s, t);
}

Compilation message (stderr)

walk.cpp: In function 'void append(int, int)':
walk.cpp:49:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   49 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
walk.cpp: In function 'long long int solve_using_segtree(vi, vi, vi, vi)':
walk.cpp:247:25: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
  247 |    if (xx1[hh[h]] == (n - 1 << 1 | 1))
      |                       ~~^~~

• Subtask 1: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 18 / 18
• Subtask 5: 0 / 43