[题目] [预备知识] ,其中r是欧拉常数,const double r= 0.57721566490153286060651209; 这个等式在n很大 的时候 比较精确. [解法]可以在 n较小的时候,比如n<1e6时,直接用预处理的打表O(1)求值,在n比较 大的时候,运用以上公式,此时要减去 1/(2*n)加以修正. #include<iostream> #include<cmath> using namespace std; const double euler= 0…

/* LightOJ1234 Harmonic Number http://lightoj.com/login_main.php?url=volume_showproblem.php?problem=1234 打表 分块 由于只有加法运算,1e8时间是可以承受的. 然而空间无法承受,于是以50个单位为一块进行分块. */ #include <cstdio> #include <algorithm> #include <cstring> #include <cmat…

题目链接:https://vjudge.net/problem/LightOJ-1234 1234 - Harmonic Number    PDF (English) Statistics Forum Time Limit: 3 second(s) Memory Limit: 32 MB In mathematics, the nth harmonic number is the sum of the reciprocals of the first n natural numbers: In…

题意:求f(n)=1/1+1/2+1/3+1/4-1/n   (1 ≤ n ≤ 108).,精确到10-8    (原题在文末) 知识点:      调和级数(即f(n))至今没有一个完全正确的公式,但欧拉给出过一个近似公式:(n很大时)       f(n)≈ln(n)+C+1/2*n       欧拉常数值:C≈0.57721566490153286060651209       c++ math库中,log即为ln. 题解: 公式:f(n)=ln(n)+C+1/(2*n); n很小时直接求…

D - Harmonic Number Time Limit:3000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1234 Description In mathematics, the nth harmonic number is the sum of the reciprocals of the first n natural numbers: In th…

Harmonic Number Time Limit:3000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1234 Description In mathematics, the nth harmonic number is the sum of the reciprocals of the first n natural numbers: In this p…

http://lightoj.com/volume_showproblem.php?problem=1245 G - Harmonic Number (II) Time Limit:3000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1245 Description I was trying to solve problem '1234 - Harmonic…

1245 - Harmonic Number (II)   PDF (English) Statistics Forum Time Limit: 3 second(s) Memory Limit: 32 MB I was trying to solve problem '1234 - Harmonic Number', I wrote the following code long long H( int n ) {     long long res = 0;     for( int i =…

In mathematics, the nth harmonic number is the sum of the reciprocals of the first n natural numbers: In this problem, you are given n, you have to find Hn. InputInput starts with an integer T (≤ 10000), denoting the number of test cases. Each case s…

Harmonic Number In mathematics, the nth harmonic number is the sum of the reciprocals of the first n natural numbers: In this problem, you are given n, you have to find Hn. Input Input starts with an integer T (≤ 10000), denoting the number of test c…