This Gist Holds All The CodeForces 800 level question solutions

1749A.cpp

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

int solve(){
    int n,m;
    cin>>n;
    cin>>m;
    int sum=0;
    for(int i=0;i<m;i++){
        int a,b;
        cin>>a;
        cin>>b;
        sum+=a;
    }
    if(sum<((n*(n+1))/2)){
        return 1;
    }
    return 0;
}

int main(){
    int t;
    cin>>t;
    for(int i=0;i<t;i++){
        if(solve()){
            cout<<"YES\n";
        }else{
            cout<<"NO\n";
        }
    }
}

1750B.cpp

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


long long int solve(){
    string s;
    long long int l;
    cin>>l;
    cin >> s;
    long long int tx=0,x=0,y=0,ty=0;
    long long int maxNum=-100;
    for(long long int i=0;i<l;){
        while(s[i]=='0'){
            i++;
            x++;
            tx++;
        }
        while(s[i]=='1'){
            i++;
            y++;
            ty++;
        }
        long long int sx = x*x;
        long long int sy = y*y;
        long long int sb = tx*ty;
        if (maxNum < max({sx, sy, sb})){
            maxNum = max({sx, sy, sb});
        }
        x=0;y=0;
    }
    return maxNum;
}

int main(int argc, char const *argv[])
{
    long long int t=0;
    cin>>t;
    for(long long int i=0;i<t;i++){
        long long int k=solve();
        cout<<k<<'\n';
    }
    return 0;
}

1754A.cpp

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

int solve(){
    string x;
    cin>>x;
    stack<int> s;
    for(char c:x){
        if(c=='Q'){
            s.push(1);
        }else{
            if(!s.empty()){
                s.pop();
            }
        }
    }
    if(!s.empty()){
        return 0;
    }else{
        return 1;
    }
}

int main(int argc, char const *argv[])
{
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        int c;
        cin>>c;
        if(solve()) cout<<"Yes\n";
        else cout<<"No\n";
    }
    return 0;
}

1759A.cpp

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

int solver(){
    string x;
    cin >> x;
    char prev='/';
    for(char c : x){
        if(c!='Y' && c!='e' && c!='s'){
            return 0;
        }
        if(prev=='/'){
            prev=c;
        }else{
            switch(prev){
                case 'Y':
                    if(c!='e'){
                        
                        return 0;
                    }
                    prev = c;
                    break;
                case 'e':
                    if(c!='s'){
                        
                        return 0;
                    }
                    prev = c;
                    break;
                case 's':
                    if(c!='Y'){
                        
                        return 0;
                    }
                    prev = c;
                    break;
                default:
                    return 0;
            }
        }
    }
    return 1;
}

int main(int argc, char const *argv[])
{
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        if(solver()){
            cout<<"\tYES\n";
        }else{
            cout<<"\tNO\n";
        }
    }
    return 0;
}