Problem no 15: Calculate npr.

-

 QUESTION :

 

Write a program to calculate nPr. nPr represents n permutation r and value of nPr is (n!) / (n-r)!.

Example 1:

Input: n = 2, r = 1
Output: 2
Explaination: 2!/(2-1)! = 2!/1! = (2*1)/1 = 2.

Example 2:

Input: n = 3, r = 3
Output: 6
Explaination: 3!/(3-3)! = 3!/0! = 6/1 = 6.
 
ANSWER:
long long int factorial(int N){
     long long int result=1;
     for(int i=1;i<=N;i++)
     {
         result*=i;
     }
     return result;
}

 

    long long nPr(int n, int r){
        int diff=n-r;
        long long int x=factorial(n);  ..calling factorial
        long long  int y=factorial(diff); ..calling factorial
        
        long long z=x/y;
        return z;
        
    }

Comments

Post a Comment

Popular posts from this blog

problem 3: given two integers N and M. The problem is to find the number closest to N and divisible by M. If there are more than one such number, then output the one having maximum absolute value.

-
  Closest Number Given non-zero two integers N and M . The problem is to find the number closest to N and divisible by M . If there are more than one such number, then output the one having maximum absolute value .   Example 1: Input: N = 13 , M = 4 Output: 12 Explanation: 12 is the Closest Number to 13 which is divisible by 4. Example 2: Input: N = -15 , M = 6 Output: -18 Explanation: -12 and -18 are both similarly close to -15 and divisible by 6. but -18 has the maximum absolute value. So, Output is -18   ANSWER:   int closestNumber(int n , int m) { int q = n / ...
Read more

problem no 7:Given two numbers A and B, find Kth digit from right of AB.

-
 QUESTION: Given two numbers A and B , find K th digit from right of A B .   Example 1: Input: A = 3 B = 3 K = 1 Output: 7 Explanation: 3 3 = 27 and 1st digit from right is 7 Example 2: Input: A = 5 B = 2 K = 2 Output: 2 Explanation: 5 2 = 25 and second digit from right is 2. ANSWER: int kthDigit(int A,int B,int K){      long long int num=pow(A,B);      int count=0;      int rem;      while(num>0)      {                    rem=num%10;                    num=num/10;          count=count+1;          if(count!=K)          {         ...
Read more

Problem no 16: count the number of squares below N.

-
QUESTION: Consider a sample space S consisting of all perfect squares starting from 1, 4, 9 and so on. You are given a number N , you have to output the number of integers less than N in the sample space S. Example 1: Input : N = 9 Output: 2 Explanation: 1 and 4 are the only Perfect Squares less than 9. So, the Output is 2. Example 2: Input : N = 3 Output: 1 Explanation: 1 is the only Perfect Square less than 3. So, the Output is 1.   ANSWER:   int countSquares(int N) { int c=0; for(int i=1;i*i<N;i++) { c=c+1; } return c; }
Read more