Submission #105036

#	Time	Username	Problem	Language	Result	Execution time	Memory
105036		bert30702	Ancient Books (IOI17_books)	C++17	0 / 100	70 ms	63096 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];
long long minimum_walk(vector<int> p, int s) {
	long long sum = 0, cnt = 0;
	for(int i = 0; i < p.size(); i ++) boss[i] = i, sz[i] = 1;
	for(int i = 0; i < p.size(); i ++) sum += abs(i - p[i]), merge(i, p[i]);
	vector<pair<int, pii> > E;
	for(int i = 0; i + 1 < p.size(); i ++) {
		if(p[i] == i and i != s) {
			cnt ++;
			continue;
		}
		int ptr = i + 1;
		if(ptr != s and ptr + 1 < p.size() and p[ptr] == ptr) ptr ++;
		if(Find(ptr) != Find(i)) E.push_back({ptr - i, {i, ptr}});
	}
	sort(E.begin(), E.end());
	for(auto it: E) {
		if(Find(it.S.F) != Find(it.S.S)) {
			merge(it.S.F, it.S.S);
			sum += 2 * it.F;
		}
	}
	assert(cnt + sz[Find(s)] == p.size());
	return sum;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:21:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < p.size(); i ++) boss[i] = i, sz[i] = 1;
                 ~~^~~~~~~~~~
books.cpp:22:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < p.size(); i ++) sum += abs(i - p[i]), merge(i, p[i]);
                 ~~^~~~~~~~~~
books.cpp:24:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i + 1 < p.size(); i ++) {
                 ~~~~~~^~~~~~~~~~
books.cpp:30:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(ptr != s and ptr + 1 < p.size() and p[ptr] == ptr) ptr ++;
                   ~~~~~~~~^~~~~~~~~~
In file included from /usr/include/c++/7/cassert:44:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:33,
                 from books.cpp:1:
books.cpp:40:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  assert(cnt + sz[Find(s)] == p.size());
         ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~

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