Submission #1124635

#	Time	Username	Problem	Language	Result	Execution time	Memory
1124635		gdragon	Palindrome-Free Numbers (BOI13_numbers)	C++20	100 / 100	42 ms	328 KiB

numbers

#include <bits/stdc++.h>
using namespace std;
#define TASK "long"
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define GETBIT(mask, i) ((mask) >> (i) & 1)
#define MASK(i) ((1LL) << (i))
#define SZ(x) ((int)(x).size())
#define mp make_pair
#define CNTBIT(mask) __builtin_popcount(mask)
template<class X, class Y> bool maximize(X &x, Y y){ if (x < y) {x = y; return true;} return false;};
template<class X, class Y> bool minimize(X &x, Y y){ if (x > y) {x = y; return true;} return false;};
typedef pair<int, int> ii;
const int N = 1e5 + 5;
const int inf = 1e9 + 7;
const long long INF = (long long)1e18 + 7;
const int mod = 1e9 + 7;
void add(int &x, int y) {x += y; if (x >= mod) x -= mod;}
void sub(int &x, int y) {x -= y; if (x < 0) x += mod;}
int mul(int x, int y) {return 1LL * x * y % mod;}
// -----------------------------------------//
long long a, b;
long long pw[20];
int getNum(long long x, int i) {
    return x / pw[i] % 10;
}
void read() {
    cin >> a >> b;
}
void sub1() {
    int ans = 0;
    for(long long i = a; i <= b; i++) {
        int j = 18;
        bool ok = 1;
        while(j >= 0 && getNum(i, j) == 0) --j;
        for(; j >= 0; j--) {
            if (j >= 1 && getNum(i, j) == getNum(i, j - 1)) ok = 0;
            if (j >= 2 && getNum(i, j) == getNum(i, j - 2)) ok = 0;
        }
        ans += ok;
    }
    cout << ans;
}
long long dp[20][11][11][2][2];
// (pos, num(i - 1), num(i), under, started)
long long calDp(long long x, int pos = 18, int v1 = 0, int v2 = 0, bool under = 0, bool started = 0) {
    if (pos < 0) return 1;
    long long &res = dp[pos][v1][v2][under][started];
    if (res != -1) return res;
    res = 0;
    int num = (under ? 9: getNum(x, pos));
    for(int c = 0; c <= num; c++) {
        bool newUnder = (under | (c < num));
        bool newStarted = (started | (c > 0));
        if (!started) {
            if (newStarted) res += calDp(x, pos - 1, 10, c, newUnder, newStarted);
            else res += calDp(x, pos - 1, 0, 0, newUnder, newStarted);
        }
        else {
            if (c != v1 && c != v2) res += calDp(x, pos - 1, v2, c, newUnder, newStarted);
        }
    }
    return res;
}
void lastsub() {
    memset(dp, -1, sizeof(dp));
    long long ans = calDp(b);
    memset(dp, -1, sizeof(dp));
    ans -= calDp(a - 1);
    cout << ans;   
}
void solve() {
    if (b - a <= 1000000) sub1();
    else lastsub();
}
signed 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);
    }
    pw[0] = 1;
    for(int i = 1; i <= 18; i++) pw[i] = pw[i - 1] * 10;
    int test = 1;
    // cin >> test;
    while(test--) {
        read();
        solve();
    }
    return 0;
}

Compilation message (stderr)

numbers.cpp: In function 'int main()':
numbers.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
numbers.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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