Submission #67546393

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Source Code Expand

#include<bits/stdc++.h>
#define int long long
using namespace std;

bool isPalindrome(const string& s) {
    int l = 0, r = s.size()-1;
    while(l < r) {
        if(s[l++] != s[r--]) return false;
    }
    return true;
}

string convertToBase(int n, int b) {
    if(n == 0) return "0";
    string ans;
    while(n > 0) {
        ans += to_string(n % b);
        n /= b;
    }
    reverse(ans.begin(), ans.end());
    return ans;
}

void generatePalindromes(int N, set<int>& palindromes) {
    // Single-digit palindromes
    for(int i = 1; i <= 9; ++i) {
        palindromes.insert(i);
    }
    
    // Generate palindromes with even and odd lengths
    for(int length = 2; length <= to_string(N).length(); ++length) {
        int half = (length + 1) / 2;
        int start = pow(10, half - 1);
        int end = pow(10, half) - 1;
        
        for(int num = start; num <= end; ++num) {
            string prefix = to_string(num);
            string suffix = prefix.substr(0, length / 2);
            reverse(suffix.begin(), suffix.end());
            string str = prefix + suffix;
            int candidate = stoll(str);
            if(candidate <= N) {
                palindromes.insert(candidate);
            }
        }
    }
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    int A, N;
    cin >> A >> N;
    
    set<int> palindromes;
    generatePalindromes(N, palindromes);
    
    int sum = 0;
    for(int num : palindromes) {
        if(num > N) continue;
        
        string baseA = convertToBase(num, A);
        if(isPalindrome(baseA)) {
            sum += num;
        }
    }
    
    cout << sum << "\n";
    
    return 0;
}

Submission Info

Compile Error

Main.cpp: In function ‘void generatePalindromes(long long int, std::set<long long int>&)’:
Main.cpp:31:32: warning: comparison of integer expressions of different signedness: ‘long long int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   31 |     for(int length = 2; length <= to_string(N).length(); ++length) {
      |                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

Judge Result