Submission #1007271

#	Time	Username	Problem	Language	Result	Execution time	Memory
1007271		Amr	Longest Trip (IOI23_longesttrip)	C++17	85 / 100	26 ms	600 KiB

longesttrip

#include "longesttrip.h"
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define F first
#define S second
#define sz size()
#define all(x) (x).begin(), (x).end()
vector<int> v1,v2;
vector<int> go(ll x, ll y)
{
    if(x) reverse(all(v1));
    if(y) reverse(all(v2));
    for(int i = 0; i < v2.sz; i++) v1.push_back(v2[i]);
    return v1;
}
std::vector<int> longest_trip(int N, int D)
{
    vector<ll> sh;
    for(int i = 0; i < N; i++) sh.push_back(i);
    std::random_device rd;
    std::mt19937 g(rd());
    std::shuffle(all(sh), g);

    v1.clear(); v2.clear();
    v1.push_back(sh[0]);
    for(int ii = 1; ii < N; ii++)
    {
        int i = sh[ii];
        bool bo = are_connected({v1.back()},{i});
        if(bo==1) v1.push_back(i);
        else
        {
            if(v2.sz==0) v2.push_back(i);
            else
            {
                bo = are_connected({v2.back()},{i});
                if(bo==1) v2.push_back(i);
                else
                {
                    reverse(all(v2));
                    for(int j = 0; j < v2.sz; j++) v1.push_back(v2[j]); v2.clear();
                    v2.push_back(i);
                }
            }
        }


    }
    if(v2.sz==0) return v1;
    if(v1.sz==0) return v2;
    //if(v1.sz>v2.sz) return v1; else return v2;
    bool b1 = are_connected({v1[0]},{v2[0]});
    bool b2 = are_connected({v1[0]},{v2.back()});
    bool b3 = are_connected({v1.back()},{v2[0]});
    bool b4 = are_connected({v1.back()},{v2.back()});

    if(b1)
    {
        return go(1,0);
    }
    else if(b2)
    {
        return go(1,1);
    }
    else if(b3)
    {
        return go(0,0);
    }
    else if(b4)
    {
        return go(0,1);
    }
    // not connecteed
    bool both = are_connected(v1,v2);
    if(both==0)
    {
        if(v1.sz>v2.sz) return v1; else return v2;
    }
    // connected
    ll l = 0, r = v1.sz-1;
    while(l<r)
    {
        ll mid = (l+r)/2;
        vector<int> vv;
        for(int i = l; i <= mid; i++) vv.push_back(v1[i]);
        bool m = are_connected(vv,v2);
        if(m) r = mid; else l = mid+1;
    }
    ll node1 = l;
    l = 0, r = v2.sz-1;
    while(l<r)
    {
        ll mid = (l+r)/2;
        vector<int> vv;
        for(int i = l; i <= mid; i++) vv.push_back(v2[i]);
        bool m = are_connected(vv,{v1[node1]});
        if(m) r = mid; else l = mid+1;
    }
    ll node2 = l;
    vector<int> ans;
    for(int i = node1+1; i < v1.sz; i++) ans.push_back(v1[i]);
    for(int i = 0; i <= node1; i++) ans.push_back(v1[i]);
    for(int i = node2; i < v2.sz; i++) ans.push_back(v2[i]);
    for(int i = 0; i < node2; i++) ans.push_back(v2[i]);
    return ans;
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> go(ll, ll)':
longesttrip.cpp:15:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |     for(int i = 0; i < v2.sz; i++) v1.push_back(v2[i]);
      |                      ^
longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:43:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |                     for(int j = 0; j < v2.sz; j++) v1.push_back(v2[j]); v2.clear();
      |                                      ^
longesttrip.cpp:43:21: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   43 |                     for(int j = 0; j < v2.sz; j++) v1.push_back(v2[j]); v2.clear();
      |                     ^~~
longesttrip.cpp:43:73: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   43 |                     for(int j = 0; j < v2.sz; j++) v1.push_back(v2[j]); v2.clear();
      |                                                                         ^~
longesttrip.cpp:103:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  103 |     for(int i = node1+1; i < v1.sz; i++) ans.push_back(v1[i]);
      |                            ^
longesttrip.cpp:105:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  105 |     for(int i = node2; i < v2.sz; i++) ans.push_back(v2[i]);
      |                          ^

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 45 / 60