Submission #105043

#	Time	Username	Problem	Language	Result	Execution time	Memory
105043		bert30702	Ancient Books (IOI17_books)	C++17	12 / 100	41 ms	31872 KiB

books

#include <bits/stdc++.h>
#include "books.h"
#define pii pair<int, int>
#define F first
#define S second
using namespace std;
const int MX = 1e6 + 100;
int boss[MX], sz[MX];
int Find(int u) {
	return boss[u] == u ? u : boss[u] = Find(boss[u]);
}
void merge(int a, int b) {
	a = Find(a), b = Find(b);
	if(a == b) return;
	boss[a] = b;
	sz[b] += sz[a];
}
priority_queue<int> pq[MX];
int G[MX];
long long minimum_walk(vector<int> p, int s) {
	int n = p.size();
	long long sum = 0, cnt = 0;
	for(int i = 0; i < n; i ++) {
		boss[i] = i;
		sz[i] = 1;
		cnt += (i != s and p[i] == i);
		G[p[i]] = max(G[p[i]], i);
		G[i]    = max(G[i], p[i]);
	}
	for(int i = 0; i < n; i ++) sum += abs(i - p[i]), merge(i, p[i]);
	vector<pair<int, pii> > E;
	for(int i = 0; i + 1 < n; i ++) {
		if(p[i] == i and i != s) continue;
		if(Find(i) == Find(i + 1)) continue;
		int ptr = i + 1;
		while(ptr <= G[i] or (ptr != s and ptr < n and p[ptr] == ptr)) {
			merge(i, ptr);
			ptr ++;
		}
		if(ptr < n) {
			// cout << "E " << i << ' ' << ptr << endl;
			E.push_back({ptr - i, {i, ptr}});
		}
		// cout << i << ' ' << ptr << endl;
		i = ptr - 1;
	}
	sort(E.begin(), E.end());
	for(auto it: E) {
		if(Find(it.S.F) != Find(it.S.S)) {
			// cout << " Add " << it.S.F << ' ' << it.S.S << endl;
			merge(it.S.F, it.S.S);
			sum += 2 * it.F;
		}
	}
	// cout << cnt << ' ' << sz[Find(s)] << endl;
	assert(cnt + sz[Find(s)] >= n);
	return sum;
}

• Subtask 1: 12 / 12
• Subtask 2: 0 / 10
• Subtask 3: 0 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30