Submission #137275

#	Time	Username	Problem	Language	Result	Execution time	Memory
137275		choikiwon	Ancient Books (IOI17_books)	C++17	0 / 100	2 ms	380 KiB

books

#include "books.h"
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

const int maxn = 1000010;

int N, S;
int A[maxn], vis[maxn], Mx[maxn];
vector<pii> V;

ll minimum_walk(std::vector<int> p, int s) {
	N = p.size();
	S = s;
	for(int i = 0; i < N; i++) {
        A[i] = p[i];
	}

	ll ret = 0;
	for(int i = 0; i < N; i++) {
        if(vis[i]) continue;

        int mx = -1e9;
        int mn = 1e9;
        int cnt = 0;

        int u = i;
        while(!vis[u]) {
            vis[u] = 1;
            cnt++;

            if(u <= S) {
                mx = max(mx, u);
            }
            if(u >= S) {
                mn = min(mn, u);
            }

            ret += abs(u - A[u]);
            u = A[u];
        }

        if(cnt >= 2) V.push_back(pii(S - mx, mn - S));
	}
	V.push_back(pii(0, 0));

	sort(V.begin(), V.end());

	for(int i = (int)V.size() - 1; i >= 0; i--) {
        Mx[i] = V[i].second;
        Mx[i] = max(Mx[i], Mx[i + 1]);
	}

	int Mn = 1e9;
	for(int i = 0; i < V.size(); i++) {
        Mn = min(Mn, V[i].first + Mx[i + 1]);
	}
	ret += 2 * Mn;

	return ret;
}

Compilation message (stderr)

books.cpp: In function 'll minimum_walk(std::vector<int>, int)':
books.cpp:57:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < V.size(); i++) {
                 ~~^~~~~~~~~~

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