Harmonic number
Time Limit:3000MS
Memory Limit:32768KB
64bit IO Format:%LLD &%llusubmit 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 problem, you is given n, you have to find Hn.
Input
Input starts with an integer T (≤10000), denoting the number of test cases.
Each case is starts with a line containing an integer n (1≤n≤108).
Output
For each case, print the case number and the nth harmonic number. Errors less than 10-8 'll be ignored.
Sample Input
12
1
2
3
4
5
6
7
8
9
90000000
99999999
100000000
Sample Output
Case 1:1
Case 2:1.5
Case 3:1.8333333333
Case 4:2.0833333333
Case 5:2.2833333333
Case 6:2.45
Case 7:2.5928571429
Case 8:2.7178571429
Case 9:2.828968254
Case 10:18.8925358988
Case 11:18.9978964039
Case 12:18.9978964139
Test instructions title.
The problem: to examine the hyper-memory problems, to group storage, otherwise it will be super memory.
#include <iostream>#include<cmath>#include<cstdio>using namespacestd;Const intmaxn=1e8+5;Doublea[maxn/ ++5];//Note +5void Get(){ Doublesum=1.0; a[0]=0; a[1]=1.0; for(intI=2; i<=maxn;i++) {sum+=1.0/Double(i); if(i% +==0) A[i/ +]=sum; }}intMain () {Get(); intt,cas=1; scanf ("%d",&t); while(t--) { intN; scanf ("%d",&N); intb=n/ +; Doubleans=A[b]; for(inti=b* ++1; i<=n;i++)//attention, b*1000 .ans+=1.0/Double(i); printf ("Case %d:%.10lf\n", cas++, ans); } return 0;}
Lightoj 1234 Harmonic number (play table)