3 ms·
Sorry, can you expand on what you meant by that?
by alexchamberlain 15y ago
Sorry, can you expand on what you meant by that?
- gsa 15y agoSum of first n natural numbers is n(n+1)/2. The sum of the array, represented by s, is n(n+1)/2 - x + y (subtract x - the missing number and add y - the duplicated number) gives: 1: n(n+1)/2 - x + y = s Product of first n natural numbers is represented as: n! The product of the numbers in array is p. 2: p x / y = n! (multiply by x - add missing number to product and divide by y - remove duplicated number from product).
- emillon 15y agoIf a is duplicated and b missing, computing the sum and the product of all the numbers can give you a-b and a/b, from which you can deduce a and b.