Submission #846587

#	Time	Username	Problem	Language	Result	Execution time	Memory
846587		math_rabbit_1028	Longest Trip (IOI23_longesttrip)	C++17	15 / 100	11 ms	1108 KiB

longesttrip

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

int find_connected(vector<int> v, vector<int> arr) {
    if (arr.size() == 0 || !are_connected(v, arr)) return -1;

    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 arr[s];
}

int find_connected_idx(vector<int> v, vector<int> arr) {
    if (arr.size() == 0 || !are_connected(v, arr)) return -1;

    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;

    vector<int> p1, p2;
    vector<int> path, clique;
    for (int i = 0; i < n; i++) {
        if (p1.size() == 0 || are_connected({p1.back()}, {i})) p1.push_back(i);
        else if (p2.size() == 0 || are_connected({p2.back()}, {i})) p2.push_back(i);
        else {
            for (int j = p2.size() - 1; j >= 0; j--) p1.push_back(p2[j]);
            p2.clear();
            p2.push_back(i);
        }
    }

    path = p1;
    clique = p2;

    bool connected = false;
    if (path.size() > 0 && clique.size() > 0) connected = are_connected(path, clique);
    if (connected) {
        int target = find_connected({path[0]}, clique);
        if (target != -1) {
            res = path;
            reverse(res.begin(), res.end());
            int t = 0;
            for (t = 0; t < clique.size(); t++) if (clique[t] == target) break;
            swap(clique[0], clique[t]);                    
            for (int j = 0; j < clique.size(); j++) res.push_back(clique[j]);
            return res;
        }
        int s = path.size() - 1;
        target = find_connected({path[s]}, clique);
        if (target != -1) {
            res = path;
            int t = 0;
            for (t = 0; t < clique.size(); t++) if (clique[t] == target) break;
            swap(clique[0], clique[t]);
            for (int j = 0; j < clique.size(); j++) res.push_back(clique[j]);
            return res;
        }

        int idx = find_connected_idx(path, clique);
        target = find_connected({clique[idx]}, path);
        swap(clique[idx], clique.back());
        res = clique;
        while (path[0] != target) {
            int front = path[0];
            path.erase(path.begin());
            path.push_back(front);
        }
        for (int k = 0; k < path.size(); k++) res.push_back(path[k]);
        return res;
    }
    else {
        if (path.size() > clique.size()) return path;
        return clique;
    }
    return {}; // never reached
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:60:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |             for (t = 0; t < clique.size(); t++) if (clique[t] == target) break;
      |                         ~~^~~~~~~~~~~~~~~
longesttrip.cpp:62:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |             for (int j = 0; j < clique.size(); j++) res.push_back(clique[j]);
      |                             ~~^~~~~~~~~~~~~~~
longesttrip.cpp:70:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |             for (t = 0; t < clique.size(); t++) if (clique[t] == target) break;
      |                         ~~^~~~~~~~~~~~~~~
longesttrip.cpp:72:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |             for (int j = 0; j < clique.size(); j++) res.push_back(clique[j]);
      |                             ~~^~~~~~~~~~~~~~~
longesttrip.cpp:85:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |         for (int k = 0; k < path.size(); k++) res.push_back(path[k]);
      |                         ~~^~~~~~~~~~~~~

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