1924A - Did We Get Everything Covered - CodeForces Solution

#include<bits/stdc++.h>

using namespace std;


#define take(x) int x;cin>>x;
#define give(x) cout <<x<<nline;
#define tvec(x,n) for (int i = 0; i < n; i++){cin >>x[i]; }
#define tvec1(x,n) for (int i = 1; i <= n; i++){cin >>x[i]; }
#define gvec(x,n) for (int i = 0; i < n; i++){cout <<x[i]<<" "; }cout<<nline;
#define gvec1(x,n) for (int i = 1; i <= n; i++){cout <<x[i]<<" "; }cout<<nline;
#define each(a, b) for (auto&(a) : (b))
#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define mod 1000000007
#define mod1 998244353
#define inf 1e18
#define nline "\n"
#define LB lower_bound
#define UB upper_bound
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ff first
#define ss second
#define PI 3.141592653589793238462
#define setbits __builtin_popcountll
#define frontzero __builtin_clzll 
#define backzero __builtin_ctzll
#define parity __builtin_parityll
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define reset(a, b) memset(a, b, sizeof(a))
template<typename S,typename T> void smax(S &a, const T &b) { if (a<b) a=b;}
template<typename S,typename T> void smin(S &a, const T &b) { if (a>b) a=b;}

typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<string, string> pss;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
// typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update > pbds; // find_by_order, order_of_key

#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif

void _print(ll t) {cerr << t;}
void _print(int t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}

template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T> void _print(T arr[]);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);
template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}
int mindfuk=1;
template <class T> void _print(T arr[]){cerr << "[ "; for (int i=0;i<mindfuk ;i++) {_print(arr[i]); cerr << " ";} cerr << "]";}



void comeon(){
    take(n);take(k);take(m);
    string s; cin>>s;
    int total=0;
    int cnt=0;string ans;
    int alpha[k];memset(alpha,0,sizeof(alpha));
    for (int i = 0; i < m; i++)
    {
        if(alpha[s[i]-'a']==0){
            cnt++;alpha[s[i]-'a']=1;
        }
        if(cnt==k){ans.push_back(s[i]);debug(i);
            total++;cnt=0;memset(alpha,0,sizeof(alpha));
        }
    }debug(ans);debug(total);
    if(total>=n){
        cout<<"yes"<<nline;return;
    }
    for (int i = 0; i < k; i++)
    {
        if(alpha[i]==0){char xx='a'+i;
            for (int j = 0; j < n-total; j++)
            {
                ans.pb(xx);
            } break;
        }
       
    }
give("no");give(ans);
    
}

int main() {
    fastio();
    
    int TC =1;
    cin >> TC;
    while(TC--) comeon();

}