Submission #67553282

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Source Code Expand

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <cmath>
using namespace std;
#define ll long long
#define faster ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

bool check_pal(string s) {
    int left = 0;
    int right = s.size() - 1;
    while (left < right) {
        if (s[left] != s[right]) {
            return false;
        }
        left++;
        right--;
    }
    return true;
}

string toBaseA(ll num, int a) {
    if (num == 0) {
        return "0";
    }
    string dg = "";
    while (num > 0) {
        int digit = num % a;
        dg += to_string(digit);
        num /= a;
    }
    reverse(dg.begin(), dg.end());
    return dg;
}

vector<ll> calPs(ll n) {
    vector<ll> P; 
    
    string nStr = to_string(n);
    int maxL = nStr.size();
    
    for (int len = 1; len <= maxL; len++) {
        int halfLen = (len + 1) / 2;
        ll start = pow(10, (len - 1) / 2);
        ll end = pow(10, halfLen) - 1;
        
        for (ll i = start; i <= end; i++) {
            string fiHalf = to_string(i);
            string PStr; 
            if (len % 2 == 0) {
                string seHalf = fiHalf;
                reverse(seHalf.begin(), seHalf.end());
                PStr = fiHalf + seHalf;
            } else {
                string seHalf = fiHalf.substr(0, fiHalf.size() - 1);
                reverse(seHalf.begin(), seHalf.end());
                PStr = fiHalf + seHalf;
            }
            ll num = stoll(PStr);
            if (num > n) {
                break;
            }
            P.push_back(num);
        }
    }
    
    return P;
}

int main() {
    faster

    int a;
    ll n;
    cin >> a >> n;
    
    vector<ll> P = calPs(n);
    
    ll sum = 0;
    for (ll num : P) {
        string baseA = toBaseA(num, a);
        bool check = true;
        for (char d : baseA) {
            if (d - '0' >= a) {
                check = false;
                break;
            }
        }
        if (check && check_pal(baseA)) {
            sum += num;
        }
    }
    
    cout << sum << endl;
    
    return 0;
}

Submission Info

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