Submission #371121

#	Time	Username	Problem	Language	Result	Execution time	Memory
371121		doowey	Ancient Books (IOI17_books)	C++14	70 / 100	244 ms	31684 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 + 100;
int lef[N], rig[N];
bool vis[N];
bool has[N];

int tl, tr;


void extend(int &li, int &ri){
    int ni = min(lef[li],lef[ri]);
    int nj = max(rig[li],rig[ri]);
    while(li > ni || ri < nj){
        if(li > ni){
            li--;
            ni = min(ni, lef[li]);
            nj = max(nj, rig[li]);
        }
        else{
            ri++;
            ni = min(ni, lef[ri]);
            nj = max(nj, rig[ri]);
        }
    }
}

int disl[N];
int disr[N];


int solve(int li, int ri){
    int cnt = 0;
    extend(li, ri);
    while(li != tl || ri != tr){
        if(li == tl){
            cnt += 2;
            ri ++ ;
        }
        else if(ri == tr){
            cnt += 2;
            li -- ;
        }
        else{
            if(li > tl && disl[li-1] < disr[ri+1]){
                li -- ;
                cnt += 2;
            }
            else{
                ri ++ ;
                cnt += 2;
            }
        }
        extend(li,ri);
    }
    return cnt;
}
long long minimum_walk(vector<int> p, int s) {
	n = p.size();
	int id;
	int low, high;
	ll sol = 0;
    tl = tr = s;
	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;
            }
        }
        if(p[i] != i){
            tl = min(tl, i);
            tr = max(tr, i);
        }
	}
    for(int i = 0 ; i < n; i ++ ){
        disl[i] = (int)1e9;
        if(rig[i] >= s)
            disl[i]=0;
        else{
            if(lef[i] == i){
                if(i>0)disl[i]=disl[i-1]+2;
            }
            else{
                disl[i]=min(disl[i],disl[i-1]);
                disl[i]=min(disl[i],disl[lef[i]]);
            }

        }
    }
    for(int i = n - 1; i >= 0 ; i -- ){
        disr[i]=(int)1e9;
        if(lef[i] <= s)
            disr[i]=0;
        else{
            if(rig[i] == i){
                if(i+1<n) disr[i]=disr[i+1]+2;
            }
            else{
                disr[i]=min(disr[i],disr[i+1]);
                disr[i]=min(disr[i],disr[rig[i]]);
            }
        }
    }
	return sol + solve(s, s);
}

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