Submission #584154

#	Time	Username	Problem	Language	Result	Execution time	Memory
584154		Olympia	Palindrome-Free Numbers (BOI13_numbers)	C++17	65.42 / 100	1 ms	212 KiB

numbers

#include <bits/stdc++.h>
using namespace std;
bool isPalindrome (int64_t i) {
    string s = to_string(i);
    bool fine = true;
    for (int j = 0; j < s.length(); j++) {
        if (j >= 1 && s[j] == s[j - 1]) {
            fine = false;
        }
        if (j >= 2 && s[j] == s[j - 2]) {
            fine = false;
        }
    }
    return fine;
}
int64_t powerOf10 (int x) {
    //pow(10, x)
    if (x == 1) {
        return 10;
    }
    int64_t tot = 81;
    for (int i = 0; i < x - 2; i++) {
        tot *= 8;
    }
    return tot + powerOf10(x - 1);
}
int64_t res (int64_t a, int64_t b) {
    int64_t ans = 0;
    for (int64_t i = a; i <= b; i++) {
        ans += isPalindrome(i);
    }
    return ans;
}
int64_t removeAllBut2 (int64_t x) {
    string s = to_string(x);
    for (int i = 2; i < s.length(); i++) {
        s[i] = '0';
    }
    return stoll(s);
}
int64_t query (int64_t a, int64_t b) {
    if (b - a <= 1000) {
        return res(a, b);
    }
    if (a != 0) {
        return query(0, b) - query(0, a - 1);
    }
    if (a == b) {
        return a;
    }
    string s = to_string(b);
    int64_t tot = 0;
    int64_t c = 0;
    for (int i = 1; i <= 9; i++) {
        for (int j = 0; j <= 9; j++) {
            for (int k = 0; k <= 9; k++) {
                if (i == j || j == k || i == k) continue;
                c += (100 * i + 10 * j + k < 100 * (s[0] - '0') + 10 * (s[1] - '0') + (s[2] - '0'));
                if (i == s[0] - '0' && j == s[1] - '0' && k == s[2] - '0') {
                    char ch = s.front();
                    reverse(s.begin(), s.end());
                    s.pop_back();
                    reverse(s.begin(), s.end());
                    tot += query(removeAllBut2(stoll(s)), stoll(s));;
                    s = ch + s;
                }
            }
        }
    }
    tot += powerOf10((int)s.length() - 1);
    int t = s.size() - 3;
    while (t--) {
        c *= 8;
    }
    return tot + c;
}
int main() {
    int64_t a, b;
    cin >> a >> b;
    cout << query(a, b) << '\n';
}

Compilation message (stderr)

numbers.cpp: In function 'bool isPalindrome(int64_t)':
numbers.cpp:6:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    6 |     for (int j = 0; j < s.length(); j++) {
      |                     ~~^~~~~~~~~~~~
numbers.cpp: In function 'int64_t removeAllBut2(int64_t)':
numbers.cpp:36:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |     for (int i = 2; i < s.length(); i++) {
      |                     ~~^~~~~~~~~~~~

• Subtask 1: 23.75 / 25
• Subtask 2: 41.666666666666664 / 75