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题目：给出一个整数n，问1-n之间包括n在内的所有数中49出现的次数。

输入首先为一个整数T，表示接下来有T组输入。

# include <cstdio>

# include <cstring>



# define N 10000000

# define LEN 22



typedef long long int LL;



LL f[LEN][10];

LL pow10[LEN];



void init(void)

{

    pow10[0] = 1;

    for (int i = 1; i < LEN; ++i)

    {

        pow10[i] = 10*pow10[i-1];

        if (i>=2)f[i][1] = (i-1)*pow10[i-2];

     }           



    memset(f[0], 0, sizeof(f[0]));

    f[1][1] = 0;

    for (int i = 1; i < LEN; ++i)

    for (int j = 1; j < 10; ++j)

    {

        f[i][j] = f[i][j-1]+f[i][1]+(j==5 ? pow10[i-1]:0);

     }       

}



int compute(int num)

{

    int fact = 1;

    LL ret = 0;

    LL x = num;

    while (x)

    {

        int t = x % 10;

        ret += f[fact-1][t];

        ++fact;

        x/=10;

    }

    x = num, fact = 1;

    while (x)

    {        

        if (x%100 == 49) ret+=num%fact+1, fact*=100, x/=100;

        else x/=10, fact*=10;

    }

    return ret;

}



int main()

{

    LL T;

    LL x;

    

    init();

    scanf("%I64d", &T);

    while (T--)

    {

        scanf("%I64d", &x);

        printf("%I64d\n", compute(x));

    }



    return 0;

}

/*

可以对比这两道题的差异：http://acm.hdu.edu.cn/webcontest/contest_showproblem.php?cid=1432&pid=1002&ojid=0

*/