Submission #248934

#	Time	Username	Problem	Language	Result	Execution time	Memory
248934		kostia244	Ancient Books (IOI17_books)	C++17	50 / 100	412 ms	58488 KiB

books

#include "books.h"
#pragma GCC optimize("O2,unroll-loops")
#pragma GCC target("avx,avx2,sse,sse2,ssse3")
#include<bits/extc++.h>
using namespace std;
const int maxn = 1<<20;
using ll = long long;
struct oset {
	vector<int> f;
	oset() : f(maxn) {}
	int insert(int x) {
		x++;
		for(; x < maxn; x += x&-x) f[x]++;
	}
	void erase(int x) {
		x++;
		for(; x < maxn; x += x&-x) f[x]--;
	}
	int order_of_key(int x) {
		int r = 0;
		for(; x > 0; x -= x&-x) r += f[x];
		return r;
	}
};
ll vis[maxn][4];
ll minimum_walk(vector<int> p, int s) {
	oset pref, suf;
	vector<int> pos(p.size());
	ll ans = 0, lst = -1, fi = -1;
	for(int i = 0; i < p.size(); i++) suf.insert(i), pos[p[i]] = i;
	for(int t, i = 0; i < p.size(); i++) {
		//cout << i << "::\n";
		
		int v = p[i];
		suf.erase(v);
		
		if(i != v) {
			vis[i][(v > i)*3]++;
			vis[i][1 + (pos[i]>i)]++;
		}
		
		t = i-pref.order_of_key(i+1);
		vis[i][1] += t, vis[i][3] += t;
		
		t = suf.order_of_key(i);
		vis[i][0] += t, vis[i][2] += t;
		
		pref.insert(v);
		
		if(vis[i][0] + vis[i][2] + vis[i][3] + vis[i][1]) {
			lst = i;
			if(fi == -1) fi = i;
		}
		//for(int j = 0; j < 4; j++) cout << vis[i][j] << " "; cout << endl;	
		
		if(i) {
			assert(vis[i][0] == vis[i-1][2]);
			assert(vis[i][1] == vis[i-1][3]);
		}
	}
	fi = min(fi, (ll)s);
	for(int i = fi; i <= lst; i++) {
		for(int j = 0; j < 4; j++) {
			if(i == lst && j >= 2) break;
			if(i == fi && j < 2) continue;
			if(vis[i][j] == 0) {
				vis[i][j]++;
				vis[i + (j<2?-1:1)][j^3]++;
			}
		}
	}
	for(int i = 0; i < p.size(); i++) {
		//cout << vis[i][0] << " " << vis[i][1] << " " << vis[i][2] << " " << vis[i][3] << " " << g[i] << endl;
		vis[i][2] = vis[i][3] = max(vis[i][2], vis[i][3]);
		vis[i][0] = vis[i][1] = max(vis[i][0], vis[i][1]);
		ans += (vis[i][0] + vis[i][2]);
	}
	return ans;
}

Compilation message (stderr)

books.cpp: In member function 'int oset::insert(int)':
books.cpp:14:2: warning: no return statement in function returning non-void [-Wreturn-type]
  }
  ^
books.cpp: In function 'll minimum_walk(std::vector<int>, int)':
books.cpp:30:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < p.size(); i++) suf.insert(i), pos[p[i]] = i;
                 ~~^~~~~~~~~~
books.cpp:31:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int t, i = 0; i < p.size(); i++) {
                    ~~^~~~~~~~~~
books.cpp:72:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < p.size(); i++) {
                 ~~^~~~~~~~~~

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