hdu 3555 数位dp

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

__int64 dp[20][3];
int  T;
__int64 n;

void init()
{
    memset(dp, 0, sizeof(dp));
    dp[0][0] = 1;

    for(int i = 1; i < 20; i++)
    {
        dp[i][0] = dp[i-1][0]*10 - dp[i-1][1];
        dp[i][1] = dp[i-1][0];
        dp[i][2] = dp[i-1][2]*10 + dp[i-1][1];
    }

}

__int64 solve(__int64 n)
{
    int a[30];
    int flag = 0;
    __int64 ans = 0;
    int len = 0;
    while(n)
    {
        a[++len] = n%10;
        n /= 10;
    }
    a[len+1] = 0;
    for(int i = len; i >= 1; i--)
    {
        ans += dp[i-1][2]*a[i];
        if(flag)
            ans += dp[i-1][0]*a[i];
        if(!flag && a[i] > 4)
            ans += dp[i-1][1];
        if(a[i+1] == 4 && a[i] == 9)
             flag = 1;
    }

    return ans;
}

int main()
{
    scanf("%d", &T);
    init();
    while(T--)
    {
        scanf("%I64d", &n);

        printf("%I64d\n", solve(n+1));

    }
    return 0;
}