Submission #528315

#	Time	Username	Problem	Language	Result	Execution time	Memory
528315		CherryMagic	Palindrome-Free Numbers (BOI13_numbers)	C++14	15 / 100	1 ms	340 KiB

numbers

#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>

using namespace std;

int a,b;
vector<int> num;
long dp[22][10][10][2][2];

long call(int pos, int dig1, int dig2, int notpal, int f){
    if (pos == num.size()){
        if (dig1 != dig2 && notpal) return 1;
        else return 0;
    }

    if (dp[pos][dig1][dig2][notpal][f] != -1)
        return dp[pos][dig1][dig2][notpal][f];

    long res = 0;
    int lmt;
    if (f == 0){
        lmt = num[pos];
    }
    else{
        lmt = 9;
    }
    for (int dgt=0;dgt <= lmt; dgt++){
        int ndig1, ndig2, nnotpal = notpal, nf=f;
        if (f == 0 && dgt < lmt) nf = 1;
        if ((pos >=2 && dgt == dig1) || (pos>=1 && dgt == dig2)) nnotpal=0;
        if (pos >= 1) ndig1 = dig2;
        else ndig1 = 0;
        ndig2 = dgt;
        if (nnotpal) res += call(pos+1, ndig1, ndig2, nnotpal, nf);
    }

    return dp[pos][dig1][dig2][notpal][f] = res;
}

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

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

Compilation message (stderr)

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

• Subtask 1: 10 / 25
• Subtask 2: 5 / 75