Submission #613686

#	Time	Username	Problem	Language	Result	Execution time	Memory
613686		drdilyor	Ancient Books (IOI17_books)	C++17	0 / 100	10 ms	212 KiB

books

#include <bits/stdc++.h>
#include "books.h"
#ifdef ONPC
    #include "t_debug.cpp"
#else
    #define debug(...) 42
#endif
#define sz(a) ((int)(a).size())
using namespace std;
using ll = long long;
const int INF = 1e9;
const ll INFL = 1e18;
const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rng(RANDOM);
template<typename T, typename U> istream& operator>>(istream& is, pair<T, U>& p) { return is >> p.first >> p.second; }
const int N = 2e5, LOGN = 17, MOD = 1e9+7;

ll minimum_walk_0(vector<int> p, int s) {
    int n=  sz(p);
    vector<int> done(n);
    function<int(int)> brute = [&](int cur) {
        int res = INF;
        for (int i = 0; i < n; i++) {
            if (done[i]) continue;
            done[i] = true;
            res = min(res, brute(p[i]) + abs(cur - i) + abs(i - p[i]));
        }
        if (res == INF)
            return abs(cur - s);
        else
            return res;
    };
    return brute(s);
}

long long minimum_walk(std::vector<int> p, int s) {
    int n = sz(p);

    if (n <= 4) return minimum_walk_0(p, s);

    vector<int> right(n), left(n);
    for (int i = 0; i < n; i++) {
        if (p[i] > i) right[i] = p[i] - i;
        if (p[i] < i) left[i] = i - p[i];
    }
    vector<int> res = {0};
    for (int step = 0; step < n; step++) {
        bool found = false;
        for (int i = res.back(); i < n; i++) {
            if (right[i]) {
                found = true;
                right[i] = 0;
                res.push_back(i);
                i += right[i] - 1;
            }
        }
        for (int i = n-1; i >= 0; i--) {
            if (left[i]) {
                left[i] = 0;
                res.push_back(i);
                i -= left[i] - 1;
            }
        }
    }
    res.push_back(0);
    ll distance = 0;
    for (int i = 1; i < sz(res); i++) {
        distance += abs(res[i] - res[i-1]);
    }
    for (int i = 0; i < n; i++) {

    }
    return distance;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:48:14: warning: variable 'found' set but not used [-Wunused-but-set-variable]
   48 |         bool found = false;
      |              ^~~~~

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