Submission #790940

#	Time	Username	Problem	Language	Result	Execution time	Memory
790940		fatemetmhr	Ancient Books (IOI17_books)	C++17	50 / 100	129 ms	29396 KiB

books

//  ~ Be Name Khoda ~  //

#include "books.h"
#include <bits/stdc++.h>
//#pragma GCC optimize ("O3")
//#pragma GCC target("avx2")
//#pragma GCC optimize("unroll-loops,Ofast")

using namespace std;

typedef long long ll;

#define pb       push_back
#define mp       make_pair
#define all(x)   x.begin(), x.end()
#define fi       first
#define se       second

const int maxn  =  1e6   + 10;
const int maxn5 =  1e6   + 10;
const int maxnt =  1.2e6 + 10;
const int maxn3 =  1e3   + 10;
const int mod   =  1e9   + 7;
const ll  inf   =  1e18;

ll ans = 0;
int per[maxn5], req[maxn5], cmp[maxn5], ps[maxn5];
int num = 0, av[maxn5], cnt = 0;
bool mark[maxn5];


void dfs(int v){
	mark[v] = true;
	req[min(v, per[v])]++;
	req[max(v, per[v])]--;
	ans += abs(v - per[v]);
	cnt++;
	cmp[v] = num;
	if(!mark[per[v]])
		dfs(per[v]);
}

int get(int l, int r){
	if(l > r)
		return 0;
	return ps[r] - (l ? ps[l - 1] : 0);
}


long long minimum_walk(std::vector<int> p, int s) {
	int n = p.size();
	int mx = 0, mn = n;
	for(int i = 0; i < n; i++){
		per[i] = p[i];
		if(i != per[i]){
			mn = min(mn, i);
			mx = max(mx, i);
		}
	}
	if(mn == n)
		return 0;
	int good = 0;
	fill(av, av + n + 5, n + 10);
	for(int i = 0; i < n; i++) if(!mark[i]){
		cnt = 0;
		dfs(i);
		if(cnt > 1)
			good++;
		num++;
	}
	int emp = 0, cur = 0;
	for(int i = 0; i < n; i++){
		cur += req[i];
		if(i)
			ps[i] = ps[i - 1];
		if(!cur)
			ps[i]++;
	}
	int add = n;
	for(int i = 0; i < n; i++) if(i != p[i])
		add = min(add, abs(i - s));
	if(mn > s || mx < s)
		add = min(abs(mx - s), abs(mn - s)) * 2;
	//cout << s << ' ' << mx << endl;
	return ans + 2 *  get(mn, mx - 1) + add;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:71:6: warning: unused variable 'emp' [-Wunused-variable]
   71 |  int emp = 0, cur = 0;
      |      ^~~

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