Submission #1274843

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274843		icebear	Palindrome-Free Numbers (BOI13_numbers)	C++20	71.25 / 100	1 ms	636 KiB

numbers

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

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 20 + 5;
ll L, R, f[N][11][11][2];
vector<int> digit;

ll dp(int pos, int last2, int last1, bool smaller) {
    if (pos == -1) return 1;
    ll &ret = f[pos][last2][last1][smaller];
    if (ret != -1) return ret;

    ret = 0;
    int limit = (smaller ? 9 : digit[pos]);
    FOR(i, 0, limit) if (last1 != i && last2 != i)
        ret += dp(pos - 1, last1, i, smaller | (i < limit));
    return ret;
}

ll calc(ll x) {
    if (x == 0) return 1;
    memset(f, -1, sizeof f);
    digit.clear();
    while(x > 0) digit.pb(x % 10), x /= 10;
    return dp((int)digit.size() - 1, 10, 10, 0);
}

void init(void) {
    cin >> L >> R;
}

void process(void) {
    cout << calc(R) - calc(L - 1);
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//    cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

numbers.cpp: In function 'int main()':
numbers.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
numbers.cpp:74:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11.25 / 25
• Subtask 2: 60 / 75