Language: C++

#include <bits/stdc++.h>
using namespace std;
#define INF 1<<30
#define endl '\n'
#define maxn 100005
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
typedef long long ll;
const double PI = acos(-1.0);
#define dbg(x) cerr << #x << " = " << x << endl;
#define dbg2(x, y) cerr << #x << " = " << x << ", " << #y << " = " << y << endl;
#define dbg3(x, y, z) cerr << #x << " = " << x << ", " << #y << " = " << y << ", " << #z << " = " << z << endl;

const ll mod = 1e9 + 7;


map<pair<int,int>, int> mp;


int main()
{
    FASTIO
   // /*
    //double start_time = clock();
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    freopen("error.txt", "w", stderr);
#endif
//*/
    int T;
    // cin >> T;
    T = 1;
    for(int cs = 1; cs <= T; cs++)
    {
        string s;
        cin >> s;
        reverse(s.begin(), s.end());
        vector<string> v = {"dream", "dreamer", "erase", "eraser"};

        for(int i = 0; i < 4; i++){
            reverse(v[i].begin(), v[i].end());
            //cerr << v[i] << endl;
        }

        bool flag = true;
        for(int i = 0; i < (int)s.length(); i++){
            bool ok = false;
            for(int j = 0; j < 4; j++){
                string x = v[j];
               // cerr << x << endl;
                if(s.substr(i, x.size()) == x){
                    ok = true;
                    i += x.size();
                }
            }
            if(!ok){#include <bits/stdc++.h>
using namespace std;
#define INF 1<<30
#define endl '\n'
#define maxn 100005
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
typedef long long ll;
const double PI = acos(-1.0);
#define dbg(x) cerr << #x << " = " << x << endl;
#define dbg2(x, y) cerr << #x << " = " << x << ", " << #y << " = " << y << endl;
#define dbg3(x, y, z) cerr << #x << " = " << x << ", " << #y << " = " << y << ", " << #z << " = " << z << endl;

const ll mod = 1e9 + 7;


map<pair<int,int>, int> mp;


int main()
{
    FASTIO
    /*
    //double start_time = clock();
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    freopen("error.txt", "w", stderr);
#endif
//*/
    int T;
    // cin >> T;
    T = 1;
    for(int cs = 1; cs <= T; cs++)
    {
        string s;
        cin >> s;
        reverse(s.begin(), s.end());
        vector<string> v = {"dream", "dreamer", "erase", "eraser"};

        for(int i = 0; i < 4; i++)
        {
            reverse(v[i].begin(), v[i].end());
            //cerr << v[i] << endl;
        }

        bool flag = true;
        for(int i = 0; i < (int)s.length();)
        {
            bool ok = false;
            for(int j = 0; j < 4; j++)
            {
                string x = v[j];
                // cerr << x << endl;
                if(s.substr(i, x.size()) == x)
                {
                    ok = true;
                    i += x.size();
                }
            }
            if(!ok)
            {
                flag = false;
                break;
            }

        }

        if(flag) cout << "YES\n";
        else cout << "NO\n";
    }

    //double end_time = clock();
    //printf( "Time = %lf ms\n", ( (end_time - start_time) / CLOCKS_PER_SEC)*1000);

    return 0;
}

                flag = false;
                break;
            }

        }

        if(flag) cout << "YES\n";
        else cout << "NO\n";
    }

    //double end_time = clock();
    //printf( "Time = %lf ms\n", ( (end_time - start_time) / CLOCKS_PER_SEC)*1000);

    return 0;
}


Compiler output:
a.cc:56:21: error: stray '#' in program
   56 |             if(!ok){#include <bits/stdc++.h>
      |                     ^
a.cc: In function 'int main()':
a.cc:56:22: error: 'include' was not declared in this scope
   56 |             if(!ok){#include <bits/stdc++.h>
      |                      ^~~~~~~
a.cc:56:31: error: 'bits' was not declared in this scope
   56 |             if(!ok){#include <bits/stdc++.h>
      |                               ^~~~
a.cc:56:36: error: 'stdc' was not declared in this scope; did you mean 'std'?
   56 |             if(!ok){#include <bits/stdc++.h>
      |                                    ^~~~
      |                                    std
a.cc:57:1: error: expected primary-expression before 'using'
   57 | using namespace std;
      | ^~~~~
a.cc:74:9: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
   74 | int main()
      |         ^~
a.cc:74:9: note: remove parentheses to default-initialize a variable
   74 | int main()
      |         ^~
      |         --
a.cc:74:9: note: or replace parentheses with braces to value-initialize a variable
a.cc:75:1: error: a function-definition is not allowed here before '{' token
   75 | {
      | ^