Submission #1011612

#	Time	Username	Problem	Language	Result	Execution time	Memory
1011612		mdn2002	Longest Trip (IOI23_longesttrip)	C++17	100 / 100	13 ms	600 KiB

longesttrip

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


vector<int> longest_trip(int N, int D) {
    vector<int> a, b, c;
    for (int i = 0; i < N; i ++) c.push_back(i);
    srand(12312);
    random_shuffle (c.begin(), c.end());
    a.push_back(c[0]);

    int not_connected = 0;
    for (int I = 1; I < N; I ++) {
        int x = a.back(), i = c[I] , y = are_connected({x}, {i});
        if (y) {
            a.push_back(i);
            not_connected = 0;
            continue;
        }

        if (b.size() == 0) {
            b.push_back(i);
            not_connected = 1;
        }
        else {
            if (not_connected) {
                b.push_back(i);
                not_connected = 1;
                continue;
            }
            int z = b.back(), k = are_connected({z}, {i});
            if (k) {
                b.push_back(i);
                not_connected = 1;
            }
            else {
                for (int j = b.size() - 1; j >= 0; j --) a.push_back(b[j]);
                b.clear();
                b.push_back(i);
            }
        }
    }

    if (b.size() == 0) return a;
    if (are_connected(a, b) == 0){
        if (a.size() > b.size()) return a;
        return b;
    }

    if (are_connected({a.back()}, {b.back()})) {
        for (int j = b.size() - 1; j >= 0; j --) a.push_back(b[j]);
        return a;
    }
    else if (are_connected({a.back()}, {b[0]})) {
        for (int j = 0; j < b.size(); j ++) a.push_back(b[j]);
        return a;
    }
    else if (are_connected({a[0]}, {b.back()})) {
        for (int j = 0; j < a.size(); j ++) b.push_back(a[j]);
        return b;
    }
    else if (are_connected({a[0]}, {b[0]})) {
        reverse(a.begin(), a.end());
        for (int j = 0; j < b.size(); j ++) a.push_back(b[j]);
        return a;
    }

    int l = 0, r = a.size(), mid;
    while (l < r) {
        mid = (l + r) / 2;
        vector<int> temp;
        for (int i = 0; i <= mid; i ++) temp.push_back(a[i]);
        if (are_connected(temp, b)) r = mid;
        else l = mid + 1;
    }
    vector<int> ans;
    for (int i = l - 1; i >= 0; i --) ans.push_back(a[i]);
    for (int i = a.size() - 1; i >= l; i --) ans.push_back(a[i]);

    int x = a[l];

    l = 0, r = b.size();
    while (l < r) {
        mid = (l + r) / 2;
        vector<int> temp;
        for (int i = 0; i <= mid; i ++) temp.push_back(b[i]);
        if (are_connected({x}, temp)) r = mid;
        else l = mid + 1;
    }

    for (int i = l; i >= 0; i --) ans.push_back(b[i]);
    for (int i = b.size() - 1; i > l; i --) ans.push_back(b[i]);

    return ans;
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:56:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |         for (int j = 0; j < b.size(); j ++) a.push_back(b[j]);
      |                         ~~^~~~~~~~~~
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 (int j = 0; j < a.size(); j ++) b.push_back(a[j]);
      |                         ~~^~~~~~~~~~
longesttrip.cpp:65:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |         for (int j = 0; j < b.size(); j ++) a.push_back(b[j]);
      |                         ~~^~~~~~~~~~

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