jmESkq - Online C++0x Compiler & Debugging Tool

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define int long long
const int MOD = 158400;
const int MOD2 = 998244353;
const int INF = LLONG_MAX/2;

int primes[1000000];

void seive(){
    fill(primes, primes + 1000000, 1);
    primes[0] = primes[1] = 0;
    for(int i = 2 ; i*i < 1000000 ; i++){
        if(primes[i]){
            for(int j = i*i ; j < 1000000 ; j += i){
                primes[j] = 0;
            }
        }
    }
    for(int i = 1 ; i < 1000000 ; i++){
        primes[i] += primes[i-1];
    }
}
int factorial(int n){
    if(n==0){
        return 1;
    }
    return (n*(factorial(n-1)))%MOD;
}
bool isPrime(int n){
    if(n <= 1) return false;
    for(int i = 2 ; i*i <= n ; i++){
        if(n % i == 0) return false;
    }
    return true;
}

int power(int a, int b){
    if(b == 0) return 1;
    a %= MOD;
    int value = power(a, b / 2);
    if(b % 2 == 0){
        return (value * value) % MOD;
    } else {
        return ((value * value) % MOD * (a % MOD)) % MOD;
    }
}

int gcd(int a, int b){
    if(a == 0) return b;
    return gcd(b % a, a);
}
void solve() {
    string s;
    int k;
    cin>>s>>k;
    int n = s.size();
    vector<pair<int,int>>maximumlengthSubstr(n);
    maximumlengthSubstr[0]= {0,1};
    int maxi = 0;
    for(int i = 1 ; i<n ; i++){
        if(abs(s[i]-s[i-1])<=k){
            int d = maximumlengthSubstr[i-1].first;
            int e = maximumlengthSubstr[i-1].second+1;
            maximumlengthSubstr[i] = {d,e};
            maxi = max(maxi,e);
        }
        else{
            int d = i;
            int e = 1;
            maximumlengthSubstr[i] = {d,e};
            maxi = max(maxi,e);
        }
    }
    string r;
    for(int i = 0 ; i<n ; i++){
        int d = maximumlengthSubstr[i].second;
        int e = maximumlengthSubstr[i].first;
        if(d==maxi){
            r = s.substr(e,d);
            break;
        }
    }
    cout<<r<<endl;
}

signed main(){
    ios::sync_with_stdio(false); cin.tie(NULL);
    //int t;
    //cin >> t;
    //while(t--){
        solve();
    //}
    return 0;
}