PROBLEM STATEMENT
There is a number of people in a room, and each of them wears a hat which is either black or white.
Every person counts the number of other people wearing white hats. You are given a vector
count, the i-th element of which is the number counted by the i-th person. Return the total number
of people wearing white hats, or -1 if count doesn't correspond to a valid situation.
DEFINITION
Class:WhiteHats
Method:whiteNumber
Parameters:vector
Returns:int
Method signature:int whiteNumber(vector count)
CONSTRAINTS
-count will contain between 2 and 50 elements, inclusive.
-Each element of count will be between 0 and 50, inclusive.
EXAMPLES
0)
{2,1,1}
Returns: 2
The first person wears a black hat and sees two people wearing white hats. Each person wearing a
white hat sees only one other white hat in the room.
1)
{2,2,2}
Returns: 3
Everyone wears a white hat here.
2)
{0,0}
Returns: 0
Black hats only.
3)
{1,1,1,2}
Returns: -1
4)
{10,10}
Returns: -1
Now that's interesting. There are only two people in the room, yet each of them counted 10 others.
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