Leftmost Digit

Description

Given a positive integer N, you should output the leftmost digit of N^N.
 

Input

The input contains several test cases. The first line of the input is a single integer T which is the number of test cases. T test cases follow.
Each test case contains a single positive integer N(1<=N<=1,000,000,000).
 

Output

For each test case, you should output the leftmost digit of N^N.
 

Sample Input

2 3 4
 

Sample Output

2 2

Hint

 In the first case, 3 * 3 * 3 = 27, so the leftmost digit is 2. In the second case, 4 * 4 * 4 * 4 = 256, so the leftmost digit is 2. 

题意:给一个整数N,要求输出N的N次方最左边的数;
分析:
令 N=X^X;
 两边同时取对数 则 log10(N)=X*log10(X);
 同时 X^X 也可以表示成 A*(10^k) 科学计数法表示
     A的整数部分即是X^X的最高位

两式合并得 log10(A)+k=X*log10(X);
log10(A)小于1 即是右式的小数部分 k是右式的整数部分
此时只需通过右式算出k即可解得A
 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<cmath>
 5 using namespace std;
 6 
 7 int main()
 8 {
 9     int T;
10     cin>>T;
11     while(T--)
12     {
13         double A,n;
14         long long k;
15         cin>>n;
16         A=n*log10(n);
17         A-=(long long)A;
18         k=pow(10.0,A);
19         cout<<k<<endl;
20     }
21 }

 

posted on 2015-02-12 16:31  wsa  阅读(167)  评论(0编辑  收藏  举报

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