Submission #387030

#	Time	Username	Problem	Language	Result	Execution time	Memory
387030		rainboy	Swapping Cities (APIO20_swap)	C++11	13 / 100	171 ms	8272 KiB

swap

#include "swap.h"
#include <cstring>
#include <vector>

const int N = 100000, M = 200000, INF = 0x3f3f3f3f;

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 ww[M];

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

		while (j < k)
			if (ww[hh[j]] == ww[h])
				j++;
			else if (ww[hh[j]] < ww[h]) {
				tmp = hh[i], hh[i] = hh[j], hh[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = hh[j], hh[j] = hh[k], hh[k] = tmp;
			}
		sort(hh, l, i);
		l = k;
	}
}

int ds[N], ww_[N], ww1[N];

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

void join(int i, int j, int w, int special) {
	i = find(i);
	j = find(j);
	if (i == j) {
		ww1[i] = min(ww1[i], w);
		return;
	}
	if (ds[i] > ds[j]) {
		ds[i] = j, ww_[i] = w;
		ww1[j] = min(ww1[j], ww1[i]);
		if (special)
			ww1[j] = min(ww1[j], w);
	} else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i, ww_[j] = w;
		ww1[i] = min(ww1[i], ww1[j]);
		if (special)
			ww1[i] = min(ww1[i], w);
	}
}

int n, m;

void init(int n_, int m_, std::vector<int> ii, std::vector<int> jj, std::vector<int> WW) {
	static int hh[M], dd[N];
	int h;

	n = n_, m = m_;
	for (h = 0; h < m; h++)
		ww[h] = WW[h], hh[h] = h;
	sort(hh, 0, m);
	memset(dd, 0, n * sizeof *dd);
	memset(ds, -1, n * sizeof *ds);
	memset(ww_, 0x3f, n * sizeof *ww_);
	memset(ww1, 0x3f, n * sizeof *ww1);
	for (h = 0; h < m; h++) {
		int i = ii[hh[h]], j = jj[hh[h]], w = ww[hh[h]];

		dd[i]++, dd[j]++;
		join(i, j, w, dd[i] > 2 || dd[j] > 2);
	}
}

int getMinimumFuelCapacity(int i, int j) {
	long long w1 = 0;

	while (i != j)
		if (ww_[i] < ww_[j])
			w1 = ww_[i], i = ds[i];
		else
			w1 = ww_[j], j = ds[j];
	while (i >= 0) {
		if (ww1[i] != INF)
			return max(w1, ww1[i]);
		i = ds[i];
	}
	return -1;
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27