Submission #708110

#	Time	Username	Problem	Language	Result	Execution time	Memory
708110		Cyanmond	Ancient Books (IOI17_books)	C++17	0 / 100	1 ms	300 KiB

books

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

using i64 = long long;

void chmax(i64 &a, i64 b) {
    if (a < b) a = b;
}

long long minimum_walk(std::vector<int> p, int s) {
    const int n = (int)p.size();
    std::vector<std::vector<int>> cycles;
    std::vector<i64> cycleCost;
    std::vector<bool> used(n);
    for (int i = 0; i < n; ++i) {
        if (used[i]) continue;
        int now = i;
        std::vector<int> cycle;
        i64 cost = 0;
        do {
            cycle.push_back(now);
            used[now] = true;
            const int nx = p[now];
            cost += std::abs(nx - now);
            now = nx;
        } while (now != i);
        if (cycle.size() == 1) {
            continue;
        }
        cycles.push_back(std::move(cycle));
        cycleCost.push_back(cost);
    }
    const int M = (int)cycles.size();
    i64 x = 0;
    for (const auto &vec : cycles) {
        chmax(x, *std::min_element(vec.begin(), vec.end()));
    }
    const i64 costSum = std::accumulate(cycleCost.begin(), cycleCost.end(), 0ll);
    return costSum + 2 * x;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:33:15: warning: unused variable 'M' [-Wunused-variable]
   33 |     const int M = (int)cycles.size();
      |               ^

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