Here i used vector of deques which resulted in Memory Limit Exceed LINK to code here

vector<deque<int>> mp(n+1);

Here i used vector of vectors which resulted in Accepted LINK to code here

vector<vector<int>> mp(n+1);

class Meeting
{
private:
    int start, end;
    Room room;

public:
    Meeting(int _start, int _end, Room _room)
    {
        start = _start;
        end = _end;
        room = _room;
    }
};
    //constructor was called
    // as calendar.push_back(Meeting(_start, _end, this));

.
.
.

[ERROR]:
 error: field ‘room’ has incomplete type ‘Room’
     Room room;
           ^~~~
a.cpp: In constructor ‘Meeting::Meeting(int, int, Room)’:
a.cpp:23:40: error: ‘_room’ has incomplete type
     Meeting(int _start, int _end, Room _room)
                                        ^~~~~

a.cpp: In member function ‘bool Room::book(int, int)’:
a.cpp:72:54: error: no matching function for call to ‘Meeting::Meeting(int&, int&, Room*)’
         calendar.push_back(Meeting(_start, _end, this));
                                                      ^

class Meeting
{
private:
    int start, end;
    Room *room;

public:
    Meeting(int _start, int _end, Room *_room)
    {
        start = _start;
        end = _end;
        room = _room;
    }
    //constructor was called
    // as Meeting(new_start,new_end,this);
..

Meeting::Meeting(int _start, int _end, Room room1):room(room1)
{
	start = _start;
	end = _end;
}
//constructor was called
// as Meeting(new_start,new_end,*this);

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define _READ freopen("input.txt", "r", stdin);
#define _FAST                         \
    ios_base::sync_with_stdio(false); \
    cin.tie(0);                       \
    cout.tie(0);
const int mod = 1e9 + 7;
void max_self(int &a,int b)
{
    a=max(a,b);
}
int32_t main()
{
    //_READ
    int n,m,w;
    cin>>n>>m>>w;
    vector<vector<int>> ar(n,vector<int>(m,0));
    for(auto &i:ar)
        for(auto &j:i)
            cin>>j;
    vector<vector<int>> items(n,vector<int>(m+1,0)); 
    for(int i=0;i<n;i++)
    {
        vector<int> prefix(m,0);
        prefix[0]=ar[i][0];
        for(int j=1;j<m;j++)
            prefix[j]=prefix[j-1]+ar[i][j];
        for(int j=0;j<m;j++)
        {
            for(int k=j;k<m;k++)
            {
                if(j>=1)
                    max_self(items[i][k-j+1],prefix[k]-prefix[j-1]);
                else if(j==0)
                    max_self(items[i][k-j+1],prefix[k]);
            }
        }
    }
    vector<int> dp(w+1,0);
    for(int i=0;i<n;i++)
    {
        vector<int> temp_dp=dp;
        vector<int> cur=dp;
        for(int j=1;j<=m;j++)//items 
        {
            for(int k=w;k>=j;k--)
            {
                max_self(temp_dp[k],temp_dp[k-j]+items[i][j]);
            }
            bool ok=true;
            // for(int k=1;k<=w;k++)
            //     cout<<temp_dp[k]<<" ";
            // cout<<"\n";
            for(int k=j;k<=w;k++)
                if(dp[k]>temp_dp[k])
                    ok=false;
            //cout<<ok<<" ";
            if(ok==true)
                for(int k=j;k<=w;k++)
                    dp[k]=temp_dp[k];   
            temp_dp=cur;
        }
        //cout<<"====\n";
    }
    cout<<*max_element(dp.begin(),dp.end());
    return 0;
}

#include <bits/stdc++.h>
#define int long long
#define F first
#define S second
#define _FAST   ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
int32_t main()
{
    _FAST
    int n, m;
    cin >> n >> m;
    vector<vector<int>> edges[n + 1];
    for (int i = 0; i < m; i++)
    {
        int a, b, c;
        cin >> a >> b >> c;
        edges[a].push_back({b, c});
    }
 
    vector<vector<int>> dist(n + 1, vector<int>(2, 1e16));
    set<vector<int>> s;
    s.insert({0,1});
 
    dist[1][0]=dist[1][1]=0;
 
    while (s.size())
    {
        vector<int> temp = *s.begin();
        s.erase(s.begin());
 
        int i = temp[1];
 
        for (vector<int> &J: edges[i])
        {
            int j = J[0];
            int now_cost = J[1];
 
            int old1 = dist[j][0];
            int old2 = dist[j][1];
 
            dist[j][0] = min(dist[j][0], dist[i][0] + now_cost);
            dist[j][1] = min({dist[j][1], dist[i][1] + now_cost, dist[i][0] + now_cost / 2});
            
            auto it=s.find({old1, j});
            auto jt=s.find({old2, j});
            
            if (old1 != dist[j][0]  && it!=s.end())
                s.erase(it);
            else
                s.insert({dist[j][0], j});
            if (old2 != dist[j][1] && jt!=s.end())
                s.erase(jt);
            else
                s.insert({dist[j][1], j});
        }
    }
    cout << min(dist[n][1], dist[n][0]);
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
vector<int> edges[100001];
vector<int> v;
vector<int> visited(100001,0);
void dfs(int i, int prev)
{
    visited[i]=1;
    for(int j:edges[i])
    {
        if(visited[j]==0)
        {
            v.push_back(j);
            dfs(j,i);
        }
        else if(j!=prev && prev!=0)
        {
            vector<int> ans;
            int index;
            for(int k=0;k<(int)v.size();k++)
            {
                if(v[k]==j)
                {
                    index=k;
                    break;
                }
            }
            for(int k=index;k<(int)v.size();k++)
                ans.push_back(v[k]);
            ans.push_back(j);
            cout<<ans.size()<<"\n";
            for(auto &i1:ans)
                cout<<i1<<" ";
            exit(0);
        }
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < m; i++)
    {
        int a, b;
        cin >> a >> b;
        edges[a].push_back(b);
        edges[b].push_back(a);
    }
    for(int i=1;i<=n;i++)
    {
        if(visited[i]==0)
        {
            v.push_back(i);
            dfs(i, 0);
            v.clear();
        }
    }
    cout<<"IMPOSSIBLE";
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define _READ freopen("input.txt", "r", stdin);
#define _FAST                         \
    ios_base::sync_with_stdio(false); \
    cin.tie(0);                       \
    cout.tie(0);
int32_t main()
{
    _FAST
    int n,w;
    cin>>n>>w;
    vector<int> dp(w+1,0);
    //dp[weight]-->maximum price can have using 
    vector<int> h(n),s(n),k(n);
    for(auto &i:h)
        cin>>i;
    for(auto &i:s)
        cin>>i;
    for(auto &i:k)
        cin>>i;
    vector<pair<int,int>> v;//weight,price
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<k[i];j++)
        {
            v.push_back({h[i],s[i]});
        }
    }
    int m=v.size();
    for(int i=0;i<m;i++)
    {
        int price=v[i].S;
        int weight=v[i].F;
        for(int j=w;j-weight>=0;j--)
            dp[j]=max(dp[j],dp[j-weight]+price);
    }
    cout<<dp[w];
    return 0;
}

Code LINK:

**CODE SNIPPET:**
void dfs(int i,int parent,set<int>& seq,vector<int> &ar,vector<int> &ans)
{
    set<int> temp=seq;
    for(auto j:edges[i])
    {
        if(j!=parent)
        {
            seq=temp;
            if(seq.lower_bound(ar[j])!=seq.end())
            {
                //auto p1=*seq.lower_bound(ar[j]);
                seq.erase(seq.lower_bound(ar[j]));
                seq.insert(ar[j]);
                ans[j]=max(ans[j],(int)seq.size());
                dfs(j,i,seq,ar,ans);
                // seq.erase(ar[j]);
                // seq.insert(p1);
            }
            else
            {
                seq.insert(ar[j]);
                ans[j]=max(ans[j],(int)seq.size());
                dfs(j,i,seq,ar,ans);
                //seq.erase(ar[j]);
            }
            // for(auto p:seq)
            //     cout<<p<<" ";
            // cout<<"\n";
            
        }
    }
}

Code LINK:

**CODE SNIPPET:**
void dfs(int i, int parent, set<int>& seq, vector<int> &ar, vector<int> &ans)
{
    int temp=-1;
    if (seq.lower_bound(ar[i]) != seq.end())
    {
        temp=*seq.lower_bound(ar[i]);
        seq.erase(seq.lower_bound(ar[i]));
        seq.insert(ar[i]);
    }
    else
        seq.insert(ar[i]);
    ans[i] = max(ans[i], (int)seq.size());
    for (auto j : edges[i])
    {
        if (j != parent)
        {
            dfs(j, i, seq, ar, ans);
        }
    }
    seq.erase(ar[i]);
    if(temp!=-1)
        seq.insert(temp);
}

Code LINK:

#include<bits/stdc++.h>
using namespace std;
typedef long long int lli;
const lli mod=1e9+7;
#define F first
#define S second
#define _READ freopen("input.txt","r", stdin);
#define pb push_back
#define _FAST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
int main()
{
    #ifndef ONLINE_JUDGE
    _READ
    #endif
    _FAST
    lli t;
    cin>>t;
    while(t--)
    {
        lli n,d;
        cin>>n>>d;
        lli low=1,high=1e18,ans=-1;
        while(low<=high)
        {
            lli x=low+(high-low)/2;
            lli temp=x+(d+x)/(x+1);
            //cout<<x<<" "<<temp<<"\n";
            if(temp<=n)
            {
                ans=x;
                break;
            }
            else
            {
                high=x-1;
            }
        }
        if(ans!=-1 || n>=d)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}

Code LINK:

#include<bits/stdc++.h>
using namespace std;
typedef long long int lli;
const lli mod=1e9+7;
#define F first
#define S second
#define _READ freopen("input.txt","r", stdin);
#define pb push_back
#define _FAST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
int main()
{
    #ifndef ONLINE_JUDGE
    _READ
    #endif
    _FAST
    lli t;
    cin>>t;
    while(t--)
    {
        lli n,d;
        cin>>n>>d;
        lli low=1,high=n-1,ans=-1;
        while(low<=high)
        {
            lli x=low+(high-low)/2;
            lli temp=x+(d+x)/(x+1);
            //cout<<x<<" "<<temp<<"\n";
            if(temp<=n)
            {
                ans=x;
                break;
            }
            else
            {
                high=x-1;
            }
        }
        if(ans!=-1 || n>=d)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}