### Problem Statement

You have a string s containing only ones and zeroes. Your goal is to make all the characters in s equal using a minimal number of operations. A single operation consists of inverting all the characters in a contiguous substring of s. Inverting a character means transforming a one into a zero, and vice versa.

For example, consider the string "0001100" (quotes for clarity). We can transform this string into all ones using 2 operations:

1. Invert the entire string: 0001100 -> 1110011.
2. Invert the substring from the 4th character to the 5th character, inclusive: 1110011 -> 1111111.

We can transform the same string into all zeros using just 1 operation:

1. Invert the substring from the 4th character to the 5th character, inclusive: 0001100 -> 0000000.
Thus, the answer for s="0001100" is 1.

You are given s as a String[]. Concatenate the elements of s to obtain the actual string, and return the minimal number of operations necessary to transform s into all ones or all zeroes.

### Definition

 Class: SwitchingBits Method: minSwitches Parameters: String[] Returns: int Method signature: int minSwitches(String[] s) (be sure your method is public)

### Constraints

-s will contain between 1 to 50 elements, inclusive.
-Each element of s will contain between 1 and 50 characters, inclusive.
-Each element of s will contain only ones ('1') and zeroes ('0').

### Examples

0)

 `{"0001100"}`
`Returns: 1`
 Invert the two ones in the middle.
1)

 `{"11111"}`
`Returns: 0`
2)

 `{"00000001"}`
`Returns: 1`
 There are two possibilities here: invert the one, or invert all the zeroes. Either way, only 1 operation is needed.
3)

 `{"1100110011001100","000","1"}`
`Returns: 4`
4)

 `{"11","101","101"}`
`Returns: 2`
 There are several ways. For example: 11101101 -> 11110011 -> 11111111 or 11101101 -> 11111101 -> 11111111

#### Problem url:

http://www.topcoder.com/stat?c=problem_statement&pm=5991

#### Problem stats url:

http://www.topcoder.com/tc?module=ProblemDetail&rd=10062&pm=5991

gevak

#### Testers:

PabloGilberto , brett1479 , Olexiy

Greedy