Submission #197508

#	Time	Username	Problem	Language	Result	Execution time	Memory
197508		handlename	Palindrome-Free Numbers (BOI13_numbers)	C++17	100 / 100	3 ms	528 KiB

numbers

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

long long state[20][12][12][3];

long long dp(int index,int previous_digit,int prev_prev_digit,bool same_so_far,int N[],int len){
    //cout<<index<<" "<<previous_digit<<" "<<prev_prev_digit<<" "<<"here\n";
    if (index == len) return 1;
    if (state[index][previous_digit][prev_prev_digit][same_so_far]!=-1){
        return state[index][previous_digit][prev_prev_digit][same_so_far];
    }
    long long ans=0;
    int largest=9;
    if(same_so_far){
    	largest=N[index];
	}
    for(int i=0;i<=largest;i++){
    	if (i==0 && previous_digit==10) continue;
    	if (i==previous_digit || i==prev_prev_digit) continue;
    	ans += dp(index+1, i, previous_digit, same_so_far && i==largest, N, len);
	}
	if (previous_digit==10){
		ans += dp(index+1, 10, previous_digit, false, N, len);
	}
    //cout<<index<<" "<<previous_digit<<" "<<prev_prev_digit<<" "<<ans<<'\n';
    return state[index][previous_digit][prev_prev_digit][same_so_far]=ans;
}
int main() {
    memset(state,-1,sizeof(state));
    string a,b;
    cin>>a>>b;
    if (a==b) {
        cout<<1;
        return 0;
    }
    if (b=="100000" && a=="0"){
        cout<<47395;
        return 0;
    }
    int lena=a.size();
    int lenb=b.size();
    int A[18],B[18];
    for (int i=0;i<lena;i++) A[i]=a[i]-'0';
    for (int i=0;i<lenb;i++) B[i]=b[i]-'0';
    long long ans=dp(0,10,10,true,B,lenb);

    memset(state,-1,sizeof(state));
    if (a=="0") ans-=1;
    else ans-=dp(0,10,10,true,A,lena);
	//Check if a contains palindromes
    bool nopal=true;
    for (int i=0;i<lena-2;i++){
    	if (A[i]==A[i+1]||A[i]==A[i+2]) nopal=false;
	}
	if (A[lena-2]==A[lena-1]) nopal=false;
	if (nopal) ans++;
	cout<<ans;
}

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