Submission #1010017

#	Time	Username	Problem	Language	Result	Execution time	Memory
1010017		boris_mihov	Overtaking (IOI23_overtaking)	C++17	65 / 100	3584 ms	47532 KiB

overtaking

#include "overtaking.h"
#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>
 
typedef long long llong;
const int MAXN = 1000 + 10;
const int MAXQ = 5000 + 10;
 
llong x;
int n, m, l;
std::vector <int> s;
std::vector <std::pair <llong,int>> buses;
std::vector <std::pair <llong,llong>> t[MAXN];
std::vector <std::pair <llong,llong>> continueThrough[MAXN];
std::vector <llong> ifBegining[MAXN];
llong min[MAXN];

int findIntersection(int pos, llong time)
{
    int l = 0, r = t[pos].size(), mid;
    while (l < r - 1)
    {
        mid = l + r >> 1;
        if (t[pos][mid].first < time) l = mid;
        else r = mid;
    }
 
    return l;
}
 
long long my_arrival_time(int pos, llong time)
{
    for (int i = pos ; i + 1 < m ; ++i)
    {
        int l = 0, r = t[i].size(), mid;
        while (l < r - 1)
        {
            mid = l + r >> 1;
            if (t[i][mid].first < time) l = mid;
            else r = mid;
        }   
 
        time = std::max(time + 1LL * x * (s[i + 1] - s[i]), t[i][l].second);
    }
 
    return time;
}
 
void init(int L, int N, std::vector <long long> T, std::vector <int> W, int X, int M, std::vector <int> S)
{
    n = N;
    m = M;
    s = S;
    x = X;
 
    for (int i = 0 ; i < n ; ++i)
    {
        buses.push_back({T[i], W[i]});
    }
 
    for (int i = 0 ; i + 1 < m ; ++i)
    {
        t[i].push_back({-1, 0});
        std::vector <std::pair <llong,int>> newBuses;
        std::sort(buses.begin(), buses.end());
        for (const auto &[time, w] : buses)
        {
            llong arrive = 1LL * (s[i + 1] - s[i]) * w + time;
            if (arrive > t[i].back().second)
            {
                t[i].push_back({time, arrive});
            }
 
            newBuses.push_back({t[i].back().second, w});
        }
 
        buses = newBuses;
    }
 
    std::vector <std::pair <int,int>> v;
    for (int i = 0 ; i + 1 < m ; ++i)
    {
        for (int j = 1 ; j < t[i].size() ; ++j)
        {
            v.push_back({i, j});
        }
    }
 
    std::sort(v.begin(), v.end(), [&](auto &a, auto &b)
    {
        return t[a.first][a.second].second - 1LL * s[a.first + 1] * x > t[b.first][b.second].second - 1LL * s[b.first + 1] * x;
    });
 
    for (int i = 0 ; i + 1 < m ; ++i)
    {
        ifBegining[i].resize(t[i].size());
        continueThrough[i].push_back({1e18, 0});
    }
    
    std::fill(min, min + m, 1e18);
    for (const auto &[i, j] : v)
    {
        bool done = false;
        ifBegining[i][j] = 1LL * (s[m - 1] - s[i + 1]) * x + t[i][j].second;
        for (int u = i + 1 ; u + 1 < m ; ++u)
        {
            if (min[u] >= t[i][j].second - 1LL * s[i + 1] * x)
            {
                continue;
            }

            int l = 0, r = t[u].size(), mid;
            while (l < r - 1)
            {
                mid = l + r >> 1;
                if (!ifBegining[u][mid]) l = mid;
                else if (t[i][j].second - 1LL * s[i + 1] * x <= t[u][mid].first - 1LL * s[u] * x) r = mid;
                else l = mid;
            }

            assert(l != 0);
            ifBegining[i][j] = ifBegining[u][l];

            // assert(r != t[u].size());
            // ifBegining[i][j] = ifBegining[u][mid];
            break;
        }
 
        min[i] = std::min(min[i], t[i][j].first - 1LL * s[i] * x);
        // continueThrough[i].push_back({t[i][j].second - 1LL * s[i] * x, std::max(continueThrough[i][j]});
    }
 
}
 
long long arrival_time(llong time)
{
    for (int i = 0 ; i + 1 < m ; ++i)
    {
        int l = 0, r = t[i].size(), mid;
        while (l < r - 1)
        {
            mid = l + r >> 1;
            if (t[i][mid].first < time) l = mid;
            else r = mid;
        }   
 
        if (l != 0 && time + 1LL * x * (s[i + 1] - s[i]) < t[i][l].second)
        {
            return ifBegining[i][l];
        }
 
        time += 1LL * x * (s[i + 1] - s[i]);
    }
 
    return time;
}

Compilation message (stderr)

overtaking.cpp: In function 'int findIntersection(int, llong)':
overtaking.cpp:26:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   26 |         mid = l + r >> 1;
      |               ~~^~~
overtaking.cpp: In function 'long long int my_arrival_time(int, llong)':
overtaking.cpp:41:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   41 |             mid = l + r >> 1;
      |                   ~~^~~
overtaking.cpp: In function 'void init(int, int, std::vector<long long int>, std::vector<int>, int, int, std::vector<int>)':
overtaking.cpp:86:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   86 |         for (int j = 1 ; j < t[i].size() ; ++j)
      |                          ~~^~~~~~~~~~~~~
overtaking.cpp:118:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  118 |                 mid = l + r >> 1;
      |                       ~~^~~
overtaking.cpp:106:14: warning: unused variable 'done' [-Wunused-variable]
  106 |         bool done = false;
      |              ^~~~
overtaking.cpp: In function 'long long int arrival_time(llong)':
overtaking.cpp:145:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  145 |             mid = l + r >> 1;
      |                   ~~^~~

• Subtask 0: 0 / 0
• Subtask 1: 9 / 9
• Subtask 2: 10 / 10
• Subtask 3: 20 / 20
• Subtask 4: 26 / 26
• Subtask 5: 0 / 35