Submission #1140915

#	Time	Username	Problem	Language	Result	Execution time	Memory
1140915		steveonalex	Ancient Books (IOI17_books)	C++20	100 / 100	115 ms	16032 KiB

books

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ull mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

#include "books.h"

const int INF = 1e9 + 69;

void update(pair<int, int> &x, pair<int, int> y){
    minimize(x.first, y.first);
    maximize(x.second, y.second);
}

ll minimum_walk(vector<int> p, int s) {
    s++;
    int n = p.size();
    for(int &i: p) i++;
    p.insert(p.begin(), 0);

    ll ans = 0;
    pair<int, int> min_range = {s, s};
    for(int i = 1; i <= n; ++i){
        ans += abs(i - p[i]);
        if (i !=p[i]){
            minimize(min_range.first, i);
            maximize(min_range.second, i);
        }
    }


    vector<pair<int,int>> big_range(n+1, {-1, -1});
    for(int i = 1; i <= n; ++i){
        if (big_range[i].first != -1) continue;
        pair<int,int> mi = {i, i};
        int j = p[i];
        while(j != i){
            minimize(mi.first, j); maximize(mi.second, j);
            j = p[j];
        }

        do{
            big_range[j] = mi;
            j = p[j];
        } while(j != i);
    }
    pair<int, int> cur = {s, s};
    pair<int, int> projected = big_range[s];
    while(true){
        while(cur.first > projected.first || cur.second < projected.second){
            if (cur.first > projected.first){
                update(projected, big_range[--cur.first]);
            }
            else{
                update(projected, big_range[++cur.second]);
            }
        }
        if (cur.first <= min_range.first && cur.second >= min_range.second) break;

        int left = 0, right = 0;
        bool check = true;
        // go left
        pair<int, int> tmp = cur, _projected = projected;
        while(tmp.first > min_range.first && tmp.second == cur.second){
            update(_projected, big_range[--tmp.first]);
            left++;
            while(tmp.first > _projected.first || tmp.second < _projected.second){
                if (tmp.first > _projected.first){
                    update(_projected, big_range[--tmp.first]);
                }
                else{
                    update(_projected, big_range[++tmp.second]);
                }
            }
        }
        if (tmp.second == cur.second) check = false;

        // go right
        tmp = cur, _projected = projected;
        while(tmp.second < min_range.second && tmp.first == cur.first){
            update(_projected, big_range[++tmp.second]);
            right++;
            while(tmp.first > _projected.first || tmp.second < _projected.second){
                if (tmp.first > _projected.first){
                    update(_projected, big_range[--tmp.first]);
                }
                else{
                    update(_projected, big_range[++tmp.second]);
                }
            }
        }
        if (tmp.first == cur.first) check = false;


        cur = tmp;
        projected = _projected;
        if (check){
            ans += min(left, right) * 2;
        }
        else{
            ans += (left + right) * 2;
            break;
        }
    }

    return ans;
}

// int main(void){
//     ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);

//     clock_t start = clock();

//     int n; cin >> n;
//     vector<int> p(n);
//     for(int i = 0; i<n; ++i) cin >> p[i];


//     int s; cin >> s;
//     cout << minimum_walk(p, s) << "\n";

//     cerr << "Time elapsed: " << clock() - start << " ms\n";
//     return 0;
// }

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