Submission #370782

#	Time	Username	Problem	Language	Result	Execution time	Memory
370782		doowey	Ancient Books (IOI17_books)	C++14	50 / 100	219 ms	26932 KiB

books

#include <bits/stdc++.h>
#include "books.h"

using namespace std;

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

#define fi first
#define se second
#define mp make_pair

int n;
const int N = (int)1e6 + 10;
int lef[N], rig[N];
bool vis[N];
bool has[N];

long long minimum_walk(vector<int> p, int s) {
	n = p.size();
	int id;
	int low, high;
	ll sol = 0;
	for(int i = 0 ; i < n; i ++ ){
        sol += abs(p[i] - i);
        if(!vis[i]){
            vector<int> cyc;
            id = i;
            while(!vis[id]){
                vis[id]=true;
                cyc.push_back(id);
                id=p[id];
            }
            low = n-1;
            high = 0;
            for(auto x : cyc){
                low = min(low, x);
                high = max(high, x);
            }
            for(auto x : cyc){
                lef[x] = low;
                rig[x] = high;
            }
        }
	}
	for(int i = 0 ; i < n ;i ++ ){
        if(i)
            rig[i] = max(rig[i], rig[i - 1]);
	}
	for(int i = n-1; i >= 0 ; i -- ){
        if(p[i] != i) has[i]=true;
        has[i]|=has[i+1];
	}
	for(int i = n-2; i >= 0 ; i -- ){
        if(i)
            lef[i] = min(lef[i], lef[i + 1]);
	}
	for(int i = 0 ; i + 1 < n; i ++ ){
        if(rig[i] <= i && lef[i + 1] > i && has[i+1]){
            sol += 2;
        }
	}
	return sol;
}

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