Submission #613774

#	Time	Username	Problem	Language	Result	Execution time	Memory
613774		drdilyor	Ancient Books (IOI17_books)	C++17	12 / 100	1 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;

long long minimum_walk(std::vector<int> p, int s) {
    int n = sz(p);
    vector<vector<int>> cycles;
    vector<pair<int,int>> range;
    vector<int> done(n);
    int distance = 0;
    int mnstart = -1;
    for (int i = 0; i < n; i++) {
        distance += abs(p[i] - i);
        if (done[i]) continue;
        if (p[i] == i) continue;
        done[i] = true;
        if (mnstart==-1) mnstart =i;
        cycles.push_back({i});
        for (int cur = p[i]; !done[cur]; cur = p[cur]) {
            cycles.back().push_back(cur);
            done[cur] = true;
        }
    }

    int k = sz(cycles);
    if (!k) return 0;

    for (int i = 0; i < k; i++) {
        int l = INF, r = 0;
        for (int i : cycles[i]) {
            l = min(l, i);
            r = max(r, i);
        }
        range.emplace_back(l, r);
    }

    int disjoint = n-1;
    for (int i = 0; i < n-1; i++) {
        bool yes = true;
        for (auto[l,r ]: range) {
            yes |= (l <= i && i < r);
        }
        disjoint -= yes;
    }

    int waste = (disjoint) * 2;
    debug(cycles, range);
    debug(waste,disjoint);

    return distance + (mnstart == -1 ? 0 : mnstart * 2) + waste;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:6:24: warning: statement has no effect [-Wunused-value]
    6 |     #define debug(...) 42
      |                        ^~
books.cpp:60:5: note: in expansion of macro 'debug'
   60 |     debug(cycles, range);
      |     ^~~~~
books.cpp:6:24: warning: statement has no effect [-Wunused-value]
    6 |     #define debug(...) 42
      |                        ^~
books.cpp:61:5: note: in expansion of macro 'debug'
   61 |     debug(waste,disjoint);
      |     ^~~~~

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