SPOJ Problem Set (classical)
1026. Favorite Dice
Problem code: FAVDICE
BuggyD loves to carry his favorite die around. Perhaps you wonder why it's his favorite? Well, his die is magical and can be transformed into an N-sided unbiased die with the push of a button. Now BuggyD wants to learn more about his die, so he raises a question:
What is the expected number of throws of his die while it has N sides so that each number is rolled at least once?
Input
The first line of the input contains an integer t, the number of test cases. t test cases follow.
Each test case consists of a single line containing a single integer N (1 <= N <= 1000) - the number of sides on BuggyD's die.
Output
For each test case, print one line containing the expected number of times BuggyD needs to throw his N-sided die so that each number appears at least once. The expected number must be accurate to 2 decimal digits.
Example
Input:
2
1
12
Output:
1.00
37.24
SOLUTION---
#include
int main()
{
int t,num,i;
scanf("%d",&t);
double ans;
while(t--)
{
ans=0.0;
scanf("%d",&num);
double k=num;
for(i=num;i>=1;i--)
{
ans+=num/k;
k=k-1;
}
printf("%.2lf\n",ans);
}
return 0;
}
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