Submission #558783

#	Time	Username	Problem	Language	Result	Execution time	Memory
558783		mr_slappy	Palindrome-Free Numbers (BOI13_numbers)	C++14	100 / 100	1 ms	340 KiB

numbers

#include "bits/stdc++.h"
#define int long long
using namespace std;
int n;
int a[20];
int dp[20][2][11][11];

int cnt(int pos,int k,int fi,int se)
{
	// cout<<pos<<' '<<k<<" "<<fi<<" "<<se<<'\n';
	if(pos==n) return 1;
	if(dp[pos][k][fi][se]!=-1) return dp[pos][k][fi][se];
	int upper=a[pos];
	if(k) upper=9;
	int ans=0;
	for(int i=0;i<=upper;i++)
	{
		if(i==fi or i==se) continue;
		if(i==0 and fi==10 and se==10)
		{
			ans+=cnt(pos+1,1,fi,se);
		}
		else
		{
			ans+=cnt(pos+1,(k or i<a[pos]),se,i);
		}
	}
	return dp[pos][k][fi][se]=ans;
}

int solve(int x)
{
	memset(dp,-1,sizeof(dp));
	n=0;
	while(x)
	{
		a[n++]=x%10;
		x/=10;
	}
	reverse(a,a+n);
	return cnt(0,0,10,10);
}

signed main()
{
	int l,r;
	cin>>l>>r;
	cout<<solve(r)-solve(l-1);
	return 0;
}

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