Submission #779108

#	Time	Username	Problem	Language	Result	Execution time	Memory
779108		vjudge1	Palindrome-Free Numbers (BOI13_numbers)	C++17	72.50 / 100	2 ms	388 KiB

numbers

#include <iostream>
#include <cstring>
using namespace std;
string tostring(long long int a) {
    if (a == 0) return "0";
    string res = "";
    while (a != 0) {
        res = char(a % 10 + 48) + res;
        a /= 10;
    }
    return res;
}
long long int f[25][2][15][15];
long long int trya(string s, int i, int smaller, int x, int y) {
    if (i == s.size()) {
        return 1;
    }
    if (f[i][smaller][x][y] != -1) return f[i][smaller][x][y];
    long long int h = 9, res = 0;
    if (smaller == 0) h = s[i] - '0';
    for (int j = 0; j <= h; j++) {
        if (j == x || j == y) continue;
        res += trya(s, i + 1, smaller | (j != h), j, x);
    }
    //cout << i << " " << smaller << " " << x << " " << y << " " << res << endl;
    f[i][smaller][x][y] = res;
    return res;
}
int main() {
    long long int l, r;
    cin >> l >> r;
    l--;
    memset(f, -1, sizeof f);
    string s = tostring(r);
    long long int h = trya(s, 0, 0, 10, 10), k;
    if (l < 0) {
        k = 0;
    }
    else {
        memset(f, -1, sizeof f);
        string t = tostring(l);
        k = trya(t, 0, 0, 10, 10);
    }
    //cout << h << " " << k << endl;
    cout << h - k;
}

Compilation message (stderr)

numbers.cpp: In function 'long long int trya(std::string, int, int, int, int)':
numbers.cpp:15:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |     if (i == s.size()) {
      |         ~~^~~~~~~~~~~

• Subtask 1: 12.5 / 25
• Subtask 2: 60 / 75