JOIN

 Problem Statement

Problem Statement for CoinFlipsDiv2

Problem Statement

You have n coins, labeled 0 through n-1. Each of the coins shows either heads or tails. You are given the states of all coins in the String state with n characters. For each i, state[i] is 'H' if coin i shows heads, or 'T' if it shows tails.

The coins are laid out in a row, ordered from coin 0 to coin n-1. A coin is called interesting if it differs from at least one of its neighbors. (For example, a coin that shows heads is interesting if at least one of its neighbors shows tails.) Return the number of interesting coins.

Definition

 Class: CoinFlipsDiv2 Method: countCoins Parameters: String Returns: int Method signature: int countCoins(String state) (be sure your method is public)

Notes

-The value of n is not given explicitly. Instead, you can determine it as the number of characters in state.

Constraints

-state will have between 1 and 50 elements, inclusive.
-Each character of state will be either 'H' or 'T'.

Examples

0)

 `"HT"`
`Returns: 2`
 Coin 0 is interesting because it shows heads and its only neighbor shows tails. Similarly, coin 1 is interesting because it shows tails and its only neighbor shows heads. Thus, the answer is 2.
1)

 `"T"`
`Returns: 0`
 In this test case there is a single coin. It has no neighbors, and therefore it has no different neighbors. This means that the coin is not interesting.
2)

 `"HHH"`
`Returns: 0`
 None of these coins are interesting, because each of them is only adjacent to coins that show the same side.
3)

 `"HHTHHH"`
`Returns: 3`
 Here, the three interesting coins are coins 1, 2, and 3. (Remember that the indices are 0-based.)
4)

 `"HHHTTTHHHTTTHTHTH"`
`Returns: 12`

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This problem was used for:
Single Round Match 681 Round 1 - Division II, Level One