Submission #467565

#	Time	Username	Problem	Language	Result	Execution time	Memory
467565		Leonardo_Paes	Palindrome-Free Numbers (BOI13_numbers)	C++17	100 / 100	1 ms	384 KiB

numbers

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

vector<int> d;
ll dp[20][2][11][11];

ll solve(int pos, bool flag, int l1, int l2){
	if(pos == d.size()) return 1;
	if(dp[pos][flag][l1][l2] != -1) return dp[pos][flag][l1][l2];
	ll tot = 0;
	if(flag){
		for(int i=0; i<10; i++){
			if(i == l1 or i == l2) continue;
			tot += solve(pos+1, flag, l2, i);
		}
	}
	else{
		for(int i=0; i<=d[pos]; i++){
			if(i == l1 or i == l2) continue;
			tot += solve(pos+1, i != d[pos] , l2, i);
		}
	}
	return dp[pos][flag][l1][l2] = tot;
}

ll calc(ll x){
	if(x < 0) return 0;
	if(x == 0) return 1;
	d.clear();
	while(x){
		d.push_back(x%10);
		x /= 10;
	}
	reverse(d.begin(), d.end());
	ll ans = 0;
	memset(dp, -1, sizeof dp);
	for(int i=0; i<d.size(); i++) ans += solve(i, i != 0, i+1 == d.size() ? 10 : 0, 10);
	return ans;
}

int main(){
	ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	ll a, b;
	cin >> a >> b;
	cout << calc(b) - calc(a-1) << "\n";
	return 0;
}

Compilation message (stderr)

numbers.cpp: In function 'll solve(int, bool, int, int)':
numbers.cpp:9:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |  if(pos == d.size()) return 1;
      |     ~~~~^~~~~~~~~~~
numbers.cpp: In function 'll calc(ll)':
numbers.cpp:38:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |  for(int i=0; i<d.size(); i++) ans += solve(i, i != 0, i+1 == d.size() ? 10 : 0, 10);
      |               ~^~~~~~~~~
numbers.cpp:38:60: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |  for(int i=0; i<d.size(); i++) ans += solve(i, i != 0, i+1 == d.size() ? 10 : 0, 10);
      |                                                        ~~~~^~~~~~~~~~~

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