Submission #1626990

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Source Code Expand

#include<bits/stdc++.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) for(int i = 0; i < (b); i++)
#define all(a) (a).begin(), (a).end()
#define show(x)  cerr << #x << " = " << (x) << endl;
//const int INF = 1e8;
using namespace std;

long long solve(string a, bool f){
	long long dp[20][2][2][2] = {{{{0}}}}; //文字、a未満である、4を含む、9を含む
	dp[0][0][0][0] = 1;
	rep(i,a.size()) rep(j,2) rep(k,2) rep(l,2) {
		int lim = j ? 9 : a[i] - '0';
		rep(d,lim + 1){
			dp[i + 1][j || d < lim][k || d == 4][l || d == 9] += dp[i][j][k][l];
		}
	}

	long long sum = 0;
	if(f){
		rep(i,2) rep(j,2) rep(k,2){
			if(j + k == 0) continue;
			sum += dp[a.size()][i][j][k];
		}
	}else{
		rep(j,2) rep(k,2){
			if(j + k == 0) continue;
			sum += dp[a.size()][1][j][k];
		}
	}
	//show(sum)
	return sum;
}


int main(){
	string a, b;
	cin >> a >> b;
	cout << solve(b, 1) - solve(a, 0) << endl;
}

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