Submission #1995479

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i))
using ll = long long;
using P = pair<int, int>;
using namespace std;

template<class T> void vin(vector<T>& v, int n) {
    v.resize(n);
    for (int i = 0; i < n; ++i) {
        cin >> v[i];
    }
}

ll dp[32][2][2];


ll solve(string S) {
    int L = S.size();
    fill(dp[0][0], dp[32][0], 0);
    dp[0][0][0] = 1;
    for (int i = 0; i < L; ++i) {
        int D = S[i] - '0';
        for (int j = 0; j < 2; ++j) {
            for (int k = 0; k < 2; ++k) {
                for (int d = 0; d <= (j ? 9 : D); ++d) {
                    dp[i + 1][j or (d < D)][k or d == 4 or d == 9] += dp[i][j][k];
                }
            }
        }
    }
    return dp[L][0][1] + dp[L][1][1];
}

int main() {
    ll A, B;
    cin >> A >> B;
    cout << solve(to_string(B)) - solve(to_string(A-1)) << endl;
    return 0;
}

Submission Info

Judge Result