Submission #900312

#	Time	Username	Problem	Language	Result	Execution time	Memory
900312		theghostking	Palindrome-Free Numbers (BOI13_numbers)	C++17	73.75 / 100	1 ms	604 KiB

numbers

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

#define int long long

vector<int> num;

int dp[20][11][11][2][2];
//pos, last digit, last last digit, tight, all 0's boolean
//10 -> no digit

int call(int pos, int lst, int lslst, int f, bool zero){
    //cout << pos << " " << lst << " " << lslst << " " << f << '\n';
    if (pos == num.size()){
        //cout << lslst << " " << lst << '\n';
        return 1;
    }
    if (dp[pos][lst][lslst][f][zero] != -1) return dp[pos][lst][lslst][f][zero];
    int res = 0;
    int lmt = 0;
    if (f == 0){
        lmt = num[pos];
    }
    else{
        lmt = 9;
    }
    for (int dgt = 0; dgt <= lmt; dgt++){
        int nf = f;
        if ((f == 0) && (dgt < lmt)) nf = 1;
        if ((dgt == 0) && (zero) && ((lst == 0) || (lslst == 0))){
            res += call(pos+1,dgt,lst,nf,zero);
        }
        if ((dgt == lst) || (dgt == lslst)) continue;
        int nz = zero;
        if (dgt > 0) nz = false;
        //cout << dgt << " " << lst << '\n';
        res += call(pos+1,dgt,lst,nf,nz);
    }
    return dp[pos][lst][lslst][f][zero] = res;
}

int solve(int b){
    num.clear();
    while (b > 0){
        num.push_back(b%10);
        b /= 10;
    }
    reverse(num.begin(),num.end());
    memset(dp,-1,sizeof(dp));
    int res = call(0,10,10,0,1);
    return res;
}

signed main() {
    int a,b;
    cin >> a >> b;
    if (a != 0){
        cout << solve(b)-solve(a-1);
    }
    else{
        cout << solve(b);
    }
    return 0;

}

Compilation message (stderr)

numbers.cpp: In function 'long long int call(long long int, long long int, long long int, long long int, bool)':
numbers.cpp:14:13: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |     if (pos == num.size()){
      |         ~~~~^~~~~~~~~~~~~

• Subtask 1: 13.75 / 25
• Subtask 2: 60 / 75