#include <iostream>
#include <string>
#include <vector>
#include <algorithm>	//for for_each
using namespace std;

int removedot0(string& s);	//remove decimal & leading and insignificant trailing 0s
string reverse(const string& s);
string MyPower(const string& s, const int n);

void out(string& s){
	cout <<s <<endl;
}

int main()
{
	string s;
	int n;
	vector<string> vs;
	while(cin>>s>>n)
		vs.push_back(MyPower(s,n));
	for_each(vs.begin(), vs.end(), out);
	system("pause");
	return 0;
}

int removedot0(string& s)	//return number of digits after the decimal point
{
	//remove heading 0s
	while(s.begin()!=s.end() && *s.begin()=='0')
		s.erase(s.begin());

	string::iterator i;
	for(i = s.begin(); i != s.end(); ++i)
	{
		if (*i == '.')	
		{
			s.erase(i); //now i points to the first digit after decimal
			break;
		}
	}
	//remove tailing 0s
	while (i!=s.end()&&*s.rbegin() =='0')
		s.erase(s.end()-1);

	return s.size()-(i-s.begin());
}

string reverse(const string& s)
{
	size_t size=s.size();
	string str(s);
	for(size_t i=0; i<size; ++i)
		str[i] = s[size-1-i];
	return str;
}

string MyPower(const string& s, const int n)
{
	if(n==0) return string("1");

	string str(s);
	int nf = removedot0(str);
	if(str=="") return string("0");

	int nf_total = nf;
	str = reverse(str);
	vector<int> vr;	//the result

	for(size_t i(0); i<str.size(); ++i)
		vr.push_back(str[i]-'0');

	for(int i(0); i<n-1; ++i)
	{
		vector<int> v(vr);	//the multiply factor
		vr.clear();

		for(size_t j(0); j<v.size()+str.size();++j)
		{
			int sum(0);
			for(size_t k=j, h=0; k>=0&&h<str.size(); ++h,--k)
				if (k<v.size()) sum+=v[k]*(str[h]-'0');
			vr.push_back(sum);
		}

		for(size_t j(0); j<vr.size();++j)
		{
			if (j==vr.size()-1)
			{
				if(vr[j]/10) vr.push_back(vr[j]/10);
			}
			else vr[j+1] +=vr[j]/10;
			vr[j] %=10;
		}
		nf_total += nf;
	}

	str="";
	for(size_t j(0); j<vr.size();++j)
		str += vr[j]+'0';
	if(nf_total) str.insert(nf_total, ".");
	return reverse(str);
}

• Re:求教：测试都通过了， 前辈给的数据也可以，但是为什么WA (25) lovepal4 2012-02-21 08:15:51