【POJ】2109 Power of Cryptography double精度

double精度强悍！Pow函数威武！EXP够神！

#include <stdio.h>
#include <math.h>

int main()
{
    double m, p;
    while(scanf("%lf%lf", &m, &p) != EOF)
    {
        printf("%.0lfn", pow(p, 1/m));
    }
    return 0;
}
-------------------------------------------------------


下面是我的错误代码：
没加二分是TLE，加了二分就WA.

#include <stdio.h>
#include <math.h>

#define MAX 120

int p[MAX];

int Len(double x)
{
    int cnt = 0;
    while(x - 1 >= 0)
    {
        cnt++;
        x /= 10;
    }
    return cnt;
}

int main()
{
    int n, i, lenp, k, j, lent, z, tp, r, midd, x, y;
    char c;
    double t, sub;
    freopen("in.txt", "r", stdin);
    while(scanf("%d", &n) != EOF)
    {
        i = 0;
        k = 1000000000;
        getchar();
        while((c = getchar()) != 'n')
        {
            if (c == EOF)
            {
                break;
            }
            p[i++] = c - '0';
        }
        lenp = i;
        x = 1;
        y = k;
        while (x < y)
        {
            midd = x + (y - x) / 2;
            t = ceil(t = pow((double)midd, (double)n));
            if ((lent = Len(t)) == lenp)
            {
                if (lent > 16)
                {
                    j = lenp - 16;
                    t = ceil(t /= pow(10, j));
                    j = 15;
                    r = 16;
                }
                else
                {
                    j = lent - 1;
                    r = lenp;
                }
                z = (int)(t / pow(10, j));
                //printf("%d", z);
                tp = 0;
                while (tp < lenp && p[tp] == z)
                {
                    sub = pow(10, j)*z;
                    tp++;
                    j--;
                    t = ceil(t -= sub);
                    z = (int)(t / pow(10, j));
                }
                if (tp == r)
                {
                    printf("%dn", midd);
                    break;
                }
                if (z > p[tp])
                {
                    y = midd;
                }
                else
                {
                    x = midd + 1;
                }
            }
            else if (lent > lenp)
            {
                y = midd;
            }
            else
            {
                x = midd + 1;
            }
        }
    }
    return 0;
}

2011-03-26 16:23 发表于百度空间，今搬至CU。