Submission #597639

#	Time	Username	Problem	Language	Result	Execution time	Memory
597639		jophyyjh	Roller Coaster Railroad (IOI16_railroad)	C++14	34 / 100	45 ms	13872 KiB

railroad

/**
 * I couldn't come up with anything except for subtasks 1-2, which can be killed
 * with the standard way of finding Hamiltonian paths.
 * 
 * After that i headed to the editorial. The method is pretty shocking to me!
 * 
 * Time Complexity: O(2^n * n^2)
 * Implementation 1
*/

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

typedef long long   ll;

const ll INF = 0x3f3f3f3f3f3f;


ll plan_roller_coaster(std::vector<int> s, std::vector<int> t) {
    int n = s.size();
    std::vector<std::vector<ll>> min_dist(1 << n, std::vector<ll>(n, INF));
    for (int i = 0; i < n; i++)
        min_dist[1 << i][i] = 0;
    for (int set = 1; set < (1 << n); set++) {
        if ((set & (set - 1)) == 0)
            continue;
        for (int last = 0; last < n; last++) {
            if (((set >> last) & 1) == 0)
                continue;
            for (int last_two = 0; last_two < n; last_two++) {
                min_dist[set][last] = std::min(
                    min_dist[set][last],
                    min_dist[set ^ (1 << last)][last_two]
                            + ll(std::max(t[last_two] - s[last], 0))
                );
            }
        }
    }
    ll min = INF;
    for (int i = 0; i < n; i++)
        min = std::min(min, min_dist[(1 << n) - 1][i]);
    return min;
}

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 0 / 30
• Subtask 4: 0 / 36