http://lightoj.com/volume_showproblem.php?problem=1245
Description
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 = 1; i <= n; i++ )
res = res + n / i;
return res;
}
Yes, my error was that I was using the integer divisions only. However, you are given n, you have to find H(n) as in my code.
Input
Input starts with an integer T (≤ 1000), denoting the number of test cases.
Each case starts with a line containing an integer n (1 ≤ n < 231).
Output
For each case, print the case number and H(n) calculated by the code.
Sample Input
11
1
2
3
4
5
6
7
8
9
10
2147483647
Sample Output
Case 1: 1
Case 2: 3
Case 3: 5
Case 4: 8
Case 5: 10
Case 6: 14
Case 7: 16
Case 8: 20
Case 9: 23
Case 10: 27
Case 11: 46475828386
#include<stdio.h> #include<math.h> #include<string.h> #include<stdlib.h> #include<algorithm> using namespace std; const int N = 10010; typedef long long ll; int main() { int t, n, p = 0; ll sum; scanf("%d", &t); while(t--) { sum = 0; p++; scanf("%d", &n); int m = sqrt(n); for(int i = 1 ; i <= m ; i++) sum += n / i; for(int i = 1 ; i <= m; i++) sum += (n / i - n / (i + 1)) * i; if(m == n / m) sum -= m; printf("Case %d: %lld ", p, sum); } return 0; }