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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
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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
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11
1
2
3
4
5
6
7
8
9
10
2147483647
Sample Output
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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
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#include<iostream> #include<cstdio> #include<cstring> #include<cmath> using namespace std; int main(){ int T, n; scanf("%d", &T); for(int ca = 1; ca <= T; ca++){ scanf("%d", &n); int te = sqrt(n); long long sum = 0; for(int i = 1; n/i > te; i++){ //sum += (n / i - n / (i +１)) * i; sum += (n / i - n / (i + 1)) * i; //cout<<sum<<endl; } for(int i = 1; i <= te; i++){ sum += n / i; } printf("Case %d: %lld\n", ca, sum); } return 0; }
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