1641.Count_Sorted_Vowel_Strings.cpp

/*
    written by Pankaj Kumar.
    country:-INDIA
    Institute: National Institute of Technology, Uttarakhand
*/
typedef long long ll ;
typedef unsigned long long ull;
typedef vector<ll> vl;
/*  Abbrevations  */
#define ff first
#define ss second
#define mp make_pair
#define pb push_back
#define Endl "\n"
#define all(V) (V).begin(),(V).end()
#define srt(V) sort(all(V))
#define srtGreat(V) sort(all(V),greater<ll>())
// some extra
#define printv(v) for(ll i=0;i<ll(v.size());i++){cout<<v[i]<<" ";} line;
#define precision(x) cout<<fixed<<setprecision(x);
#define sz(V) ll(V.size())

/* ascii value 
A=65,Z=90,a=97,z=122
*/
/*  --------------------MAIN PROGRAM----------------------------*/
// to run ctrl+b
const ll INF=LONG_MAX;
const ll mod1=1e9+7;
const ll mod2=998244353;

// add main code here
class Solution {
public:
    int countVowelStrings(int n) {
        vl v(5,1);
        vl dp(n+1,0);
        dp[1]=5;
        for(ll i=1;i<=n;i++){
            ll sum=v[0];
            for(ll j=1;j<5;j++){
                sum+=v[j];
                v[j]=sum;
            }
            dp[i]=sum;
        }
        return dp[n];
    }
};


/* -----------------END OF PROGRAM --------------------*/
/*
* stuff you should look before submission 
* constraint and time limit
* int overflow
* special test case (n=0||n=1||n=2)
* don't get stuck on one approach if you get wrong answer
*/