Submission #34584

#	Time	Username	Problem	Language	Result	Execution time	Memory
34584		ioitcprac	Palindrome-Free Numbers (BOI13_numbers)	C++14	72.50 / 100	0 ms	2052 KiB

numbers

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

typedef long long ll;

#define REP(i, n) for(ll i=0; i<n; i++)
#define FOR(i, a, b) for(ll i = a; i<=b; i++)
#define FORD(i, a, b) for(ll i = a; i>=b; i--)
#define DEBUG(x) cout<<#x<<" > "<<x<<endl;
#define endl '\n'

const ll MOD = 1e9 + 7, INF = 1e18, MX = 1e5 + 4;

ll a, b;
string s;
ll dp[20][2][11][11];

ll f(ll idx, bool b, ll pree, ll pre)
{
	if(idx == s.size())
		return 1;

	if(pre == pree && pre != 10)
		return 0;

	if(dp[idx][b][pree][pre] != -1)
		return dp[idx][b][pree][pre];

	ll ans = 0;
	FOR(i, 0, 9)
	{
		if(b == 0 && i < s[idx] - '0' && i != pree && i != pre)
		{
			ans += f(idx + 1, 1, pre, i);
		}

		if(b == 0 && i == s[idx] - '0' && i != pree && i != pre)
		{
			ans += f(idx + 1, 0, pre, i);
		}

		if(b == 1 && i != pre && i != pree)
		{
			ans += f(idx + 1, 1, pre, i);
		}
	}

	return dp[idx][b][pree][pre] = ans;
}

int main()
{	
	memset(dp, -1, sizeof(dp));
	cin >> a >> b;
	a--;
	s = to_string(a);
	ll ff = f(0, 0, 10, 10);
	s = to_string(b);
	memset(dp, -1, sizeof(dp));
	ll fff = f(0, 0, 10, 10);
	cout << fff - ff << endl;
	

}

Compilation message (stderr)

numbers.cpp: In function 'll f(ll, bool, ll, ll)':
numbers.cpp:20:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if(idx == s.size())
         ^

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