Submission #1007016

#	Time	Username	Problem	Language	Result	Execution time	Memory
1007016		edogawa_something	Longest Trip (IOI23_longesttrip)	C++17	0 / 100	55 ms	46936 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vii;
typedef pair<ll,ll> pii;
#define pb push_back
#define F first 
#define S second 
#define all(v) v.begin(),v.end()
const int M=1010;
const ll inf=1e18;
struct dsu{
    ll sz[M],pa[M];
    void init(ll x){
        for(int i=0;i<=x;i++)
        pa[i]=i,sz[i]=1;
    }
    ll get(ll x){
        if(x==pa[x])
        return x;
        return pa[x]=get(pa[x]);
    }
    void unite(ll x,ll y){
        x=get(x),y=get(y);
        if(x==y)
        return;
        if(sz[x]<sz[y])
        swap(x,y);
        pa[y]=x;
        sz[x]+=sz[y];
    }
    bool same(ll x,ll y){
        return (get(x)==get(y));
    }
}d;
ll n;
bool edge[M][M],vis[M];
bool used[M];
vector<int>ans,adj[M];
void dfs(ll x){
    if(vis[x])
    return;
    vis[x]=1;
    for(auto it:adj[x]){
        dfs(it);
    }
}
bool cchk(ll i,ll j){
    if(!edge[i][j])
    return 0;
    bool c1[260];
    memset(c1,0,sizeof c1);
    for(auto it:adj[i]){
        if(it!=j)
        c1[it]=1;
    }
    for(auto it:adj[j]){
        if(it!=i&&!c1[it])
        return 1;
    }
    return 0;
}
deque<int>dp[260][260];
vector<int> solve(ll x,ll y){
    vii v;
    v.pb(x),v.pb(y);
    for(int i=0;i<n;i++){
        if(i==x||i==y)
        continue;
        v.pb(i);
    }
    for(int i=2;i<v.size();i++){
        bool c=0;
        for(int j=i-2;j>=0;j--){
            if(edge[v[i]][v[i-1]]&&dp[j][i-1].size()>0){
            dp[j][i]=dp[j][i-1];
            dp[j][i].pb(v[i]);
            dp[i][j]=dp[i-1][j];
            dp[i][j].push_front(v[i]);
            }
            if(edge[v[i]][v[j]]&&dp[j][i-1].size()>0&&!c){
                dp[i-1][i]=dp[i-1][j];
                dp[i-1][i].pb(v[i]);
                dp[i][i-1]=dp[j][i-1];
                dp[i][i-1].push_front(v[i]);
                c=1;
            }
        }
    }
    vector<int>res;
    for(int i=0;i<n-1;i++){
        if(dp[i][n-1].size()>0){
            for(auto it:dp[i][n-1])
            res.pb(it);
            return res;
        }
    }
    return res;
}
std::vector<int> longest_trip(int N, int D)
{
    memset(vis,0,sizeof vis);
    n=N;
    for(int i=0;i<n;i++)
    adj[i].clear();
    for(int i=0;i<n;i++){
        used[i]=0;
        for(int j=0;j<n;j++)
        dp[i][j].clear();
    }
    d.init(n);
    for(int i=0;i<n;i++){
        for(int j=i+1;j<n;j++){
            edge[i][j]=edge[j][i]=are_connected({i},{j});
            if(edge[i][j])
            adj[i].pb(j),adj[j].pb(i);
        }
    }
    dfs(0);
    bool chk=0;
    for(int i=0;i<n;i++){
        if(!vis[i])
        chk=1;
    }
    if(chk){
        vector<int>v1,v2;
        v1.pb(0);
        for(int i=1;i<n;i++){
            if(edge[i][0])
            v1.pb(i);
            else
            v2.pb(i);
        }
        if(v1.size()<v2.size())
        swap(v1,v2);
        return v1;
    }
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            if(i==j)
            continue;
            if(cchk(i,j)){
                cout<<i<<' '<<j<<'\n';
                dp[0][1].pb(i),dp[0][1].pb(j);
                dp[1][0].pb(j),dp[1][0].pb(i);
                return solve(i,j);
            }
        }
    }
    if(ans.empty()){
        for(int i=0;i<n;i++)
        ans.pb(i);
    }
    return ans;
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> solve(ll, ll)':
longesttrip.cpp:73:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |     for(int i=2;i<v.size();i++){
      |                 ~^~~~~~~~~

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