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Wednesday, April 28, 2010

Array of size

Given an array of size n+1 which contains all the numbers from 1 to n. Find the number which is repeated in O(n) time. How do you proceed with the same with floating numbers from 0 to 1 instead of 1 to n?

Ans

The number appearing 2 times is (sum of all the numbers in the array) - (sum of the numbers from 1 to n). For floating numbers multiply it with 100 and proceed.

Two trains enter at the opposite

Two trains enter at the opposite sides of a tunnel of length L with speeds 'V'. A particle enters the tunnel at the same time with a speed 'v' and it vibrates in the tunnel[i.e. if it reaches the end of the tunnel then it comes back]. What is the position of the particle by the time the 2 trains meet?

Ans

If v<=2V then the position is (v*L)/(2*V) from the starting point else it is 2*L -(v*L)/(2*V) from the starting point.