Submission #66133

#	Time	Username	Problem	Language	Result	Execution time	Memory
66133		Eae02	Roller Coaster Railroad (IOI16_railroad)	C++14	34 / 100	141 ms	9540 KiB

railroad

#include "railroad.h"

#include <bits/stdc++.h>

using ll = long long;

struct Track
{
    int maxEntrySpeed;
    int exitSpeed;
};

int n;
Track tracks[16];

const ll BIG = std::numeric_limits<ll>::max();

ll memo[1 << 16][16];

ll minTrackLen(const uint16_t b, const int l)
{
    if (memo[b][l] != 0)
        return memo[b][l] - 1;
    if (b == (1 << n) - 1)
        return 0;
    
    int speed = tracks[l].exitSpeed;
    
    ll m = BIG;
    for (int i = 0; i < n; i++)
    {
        uint16_t mask = 1 << i;
        if (b & mask)
            continue;
        
        int d = std::max(speed - tracks[i].maxEntrySpeed, 0);
        m = std::min(m, minTrackLen(b | mask, i) + d);
    }
    
    memo[b][l] = m + 1;
    return m;
}

long long plan_roller_coaster(std::vector<int> s, std::vector<int> t)
{
    if (s.size() > 16)
        return 0;
    
    n = s.size();
    for (int i = 0; i < n; i++)
    {
        tracks[i].maxEntrySpeed = s[i];
        tracks[i].exitSpeed = t[i];
    }
    
    ll m = BIG;
    for (int i = 0; i < n; i++)
    {
        m = std::min(m, minTrackLen(1 << i, i));
    }
    
    return m;
}

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