Submission #313655

#	Time	Username	Problem	Language	Result	Execution time	Memory
313655		BeanZ	Palindrome-Free Numbers (BOI13_numbers)	C++14	100 / 100	1 ms	416 KiB

numbers

// I_Love_LPL
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
const int N = 5005;
vector<ll> a;
ll dp[20][2][11][11][2];
ll DP(ll id, ll h, ll s, ll f, ll p){
    if (id == a.size()) return 1;
    if (dp[id][h][s][f][p] != -1) return dp[id][h][s][f][p];
    ll res = 0;
    if (p == 0) res = res + DP(id + 1, 1, 10, 10, 0);
    for (int i = 0; i <= 9; i++){
        if (p == 0 && i == 0) continue;
        if (h == 0 && i > a[id]) continue;
        if (i != f && i != s) res = res + DP(id + 1, h | (i < a[id]), f, i, 1);
    }
    return dp[id][h][s][f][p] = res;
}
ll solve(ll u){
    if (u < 0) return 0;
    a.clear();
    while (u){
        a.push_back(u % 10);
        u /= 10;
    }
    reverse(a.begin(), a.end());
    memset(dp, -1, sizeof(dp));
    return DP(0, 0, 10, 10, 0);
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    if (fopen("A.inp", "r")){
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }
    ll a, b;
    cin >> a >> b;
    cout << solve(b) - solve(a - 1);
}
/*
*/

Compilation message (stderr)

numbers.cpp: In function 'long long int DP(long long int, long long int, long long int, long long int, long long int)':
numbers.cpp:10:12: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |     if (id == a.size()) return 1;
      |         ~~~^~~~~~~~~~~
numbers.cpp: In function 'int main()':
numbers.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   36 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
numbers.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   37 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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