Submission #1029348

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029348		kiethm07	Palindrome-Free Numbers (BOI13_numbers)	C++11	100 / 100	1 ms	464 KiB

numbers

#include <bits/stdc++.h>

#define pii pair<int,int>
#define iii pair<int,pii>
#define fi first
#define se second

#define vi vector<int>
#define vii vector<pii>
#define pb(i) push_back(i)
#define all(x) x.begin(),x.end()

#define TEXT "a"

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

const int inf = 1e9 + 7;
const ld eps = 1e-8;
const double pi = acos(-1);

ll dp[20][11][11][2][2];

string s;
int n;

string conv(ll x){
    string res = "";
    if (x == 0) return "0";
    while(x){
        res += (x % 10) + '0';
        x /= 10;
    }
    reverse(all(res));
    return res;
}

ll f(int pos,int l,int p,bool small,bool start){
    //cout << pos << " " << l << " " << p << " " << small << " " << start << "\n";
    if (pos == n) return 1;
    ll &res = dp[pos][l][p][small][start];
    if (res != -1) return res;
    int num = s[pos] - '0';
    res = 0;
    for (int i = 0; i <= 9; i++){
        bool nsmall = small | (i < num);
        bool nstart = start | (i > 0);
        if ((small == 0) && (i > num)) break;
        if (start && (i == p || i == l)) continue;
        if (nstart == 0) res += f(pos + 1,10,10,1,0);
        else res += f(pos + 1,i,l,nsmall,nstart);
    }
    return res;
}

ll cal(ll x){
    if (x < 0) return 0;
    memset(dp,-1,sizeof(dp));
    s = conv(x);
    n = s.size();
    return f(0,10,10,0,0);
}

int main(){
    cin.tie(0) -> sync_with_stdio(0);
    if (fopen(TEXT".inp","r")){
        freopen(TEXT".inp","r",stdin);
        freopen(TEXT".out","w",stdout);
    }
    ll a,b;
    cin >> a >> b;
    ll res = cal(b) - cal(a - 1);
    cout << res << "\n";
    return 0;
}

Compilation message (stderr)

numbers.cpp: In function 'int main()':
numbers.cpp:70:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |         freopen(TEXT".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
numbers.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen(TEXT".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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