Submission #847049

#	Time	Username	Problem	Language	Result	Execution time	Memory
847049		math_rabbit_1028	Longest Trip (IOI23_longesttrip)	C++17	100 / 100	15 ms	604 KiB

longesttrip

#include <bits/stdc++.h>
#include "longesttrip.h"
using namespace std;

int find_connected(vector<int> v, vector<int> arr) {
    int s = 0, e = arr.size() - 1;
    while (s < e) {
        int m = (s + e) / 2;
        vector<int> temp;
        for (int i = s; i <= m; i++) temp.push_back(arr[i]);
        if (are_connected(v, temp)) e = m;
        else s = m + 1;
    }
    return s;
}

vector<int> longest_trip(int N, int D) {
    int n = N;
    vector<int> res;

    int ch[256]; for (int i = 0; i < n; i++) ch[i] = 0;
    vector<int> p1, p2;
    p1.push_back(0);
    if (are_connected({0}, {1})) p1.push_back(1);
    else p2.push_back(1);
    for (int i = 2; i < n; i += 2) {
        if (!are_connected({p1.back()}, {i})) swap(p1, p2);
        p1.push_back(i);
        if (i == n - 1) continue;
        if (are_connected({i}, {i + 1})) {
            p1.push_back(i + 1);
            if (p2.size() == 0 || are_connected({i + 1}, {p2.back()})) {
                for (int j = p2.size() - 1; j >= 0; j--) p1.push_back(p2[j]);
                p2.clear();
            }
        }
        else {
            if (p2.size() == 0 || are_connected({i + 1}, {p2.back()})) p2.push_back(i + 1);
            else {
                p1.pop_back();
                p1.push_back(i + 1);
                p2.push_back(i);
            }
        }
    }

    bool connected = false;
    if (p1.size() > 0 && p2.size() > 0) connected = are_connected(p1, p2);
    if (connected) {
        if (p1.size() == 1 || are_connected({p1.front()}, {p1.back()})) {
            if (p2.size() == 1 || are_connected({p2.front()}, {p2.back()})) {
                int a = find_connected(p1, p2);
                int b = find_connected({p2[a]}, p1); //p2[a] - p1[b]
                for (int i = b + 1; i < p1.size(); i++) res.push_back(p1[i]);
                for (int i = 0; i <= b; i++) res.push_back(p1[i]);
                for (int i = a; i < p2.size(); i++) res.push_back(p2[i]);
                for (int i = 0; i < a; i++) res.push_back(p2[i]);
                return res;
            }
        }
        if (are_connected({p1.front()}, {p2.front()})) {
            reverse(p1.begin(), p1.end());
            for (int i = 0; i < p1.size(); i++) res.push_back(p1[i]);
            for (int i = 0; i < p2.size(); i++) res.push_back(p2[i]);
            return res;
        }
        if (are_connected({p1.front()}, {p2.back()})) {
            reverse(p1.begin(), p1.end());
            reverse(p2.begin(), p2.end());
            for (int i = 0; i < p1.size(); i++) res.push_back(p1[i]);
            for (int i = 0; i < p2.size(); i++) res.push_back(p2[i]);
            return res;
        }
        if (are_connected({p1.back()}, {p2.front()})) {
            for (int i = 0; i < p1.size(); i++) res.push_back(p1[i]);
            for (int i = 0; i < p2.size(); i++) res.push_back(p2[i]);
            return res;
        }
        if (are_connected({p1.back()}, {p2.back()})) {
            reverse(p2.begin(), p2.end());
            for (int i = 0; i < p1.size(); i++) res.push_back(p1[i]);
            for (int i = 0; i < p2.size(); i++) res.push_back(p2[i]);
            return res;
        }
    }
    else {
        if (p1.size() > p2.size()) return p1;
        return p2;
    }
    return {}; // never reached
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:54:39: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |                 for (int i = b + 1; i < p1.size(); i++) res.push_back(p1[i]);
      |                                     ~~^~~~~~~~~~~
longesttrip.cpp:56:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |                 for (int i = a; i < p2.size(); i++) res.push_back(p2[i]);
      |                                 ~~^~~~~~~~~~~
longesttrip.cpp:63:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |             for (int i = 0; i < p1.size(); i++) res.push_back(p1[i]);
      |                             ~~^~~~~~~~~~~
longesttrip.cpp:64:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |             for (int i = 0; i < p2.size(); i++) res.push_back(p2[i]);
      |                             ~~^~~~~~~~~~~
longesttrip.cpp:70:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |             for (int i = 0; i < p1.size(); i++) res.push_back(p1[i]);
      |                             ~~^~~~~~~~~~~
longesttrip.cpp:71:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   71 |             for (int i = 0; i < p2.size(); i++) res.push_back(p2[i]);
      |                             ~~^~~~~~~~~~~
longesttrip.cpp:75:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |             for (int i = 0; i < p1.size(); i++) res.push_back(p1[i]);
      |                             ~~^~~~~~~~~~~
longesttrip.cpp:76:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |             for (int i = 0; i < p2.size(); i++) res.push_back(p2[i]);
      |                             ~~^~~~~~~~~~~
longesttrip.cpp:81:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   81 |             for (int i = 0; i < p1.size(); i++) res.push_back(p1[i]);
      |                             ~~^~~~~~~~~~~
longesttrip.cpp:82:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   82 |             for (int i = 0; i < p2.size(); i++) res.push_back(p2[i]);
      |                             ~~^~~~~~~~~~~
longesttrip.cpp:21:9: warning: variable 'ch' set but not used [-Wunused-but-set-variable]
   21 |     int ch[256]; for (int i = 0; i < n; i++) ch[i] = 0;
      |         ^~

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 60 / 60