HackerRank: Paint The Tiles

Problem

Nikita has a line of N tiles indexed from 0 to N−1. She wants to paint them to match a color configuration, C, which is comprised of 2 colors: Red(R) and Blue(B)

In one stroke, Nikita can paint 1 or more adjacent tiles a single color. After she finishes painting, each tile(i) should be painted color C(i).

It should be noted that it is not allowed to apply more than 1 stroke on a tile.

Given the required color configuration, find and print the minimum number of strokes required for Nikita to paint all N tiles.

Note: In a line of tiles, 2 tiles with the indices i and j are considered adjacent only if |ji|=1.

Input Format

The first line contains a single integer, N, denoting the number of tiles to be painted.
The second line contains a string, C, denoting the desired color configuration.

For each character C(i) in C:

  • If C(i)=“R”, it means the ith tile must be painted red.
  • If C(i)=“B”, it means the ith tile must be painted blue.

Constraints

  • 1N1000
  • C(i){“R”, “B”}

Output Format

Print the minimum number of strokes required to paint all tiles in the desired color configuration.

Sample Input 0

5  
RRRRR

Sample Output 0

1

Sample Input 1

5  
RRBRR

Sample Output 1

3

Sample Input 2

5  
BRBRB

Sample Output 2

5

Explanation

Sample Case 0:

Nikita will paint all 5 consecutive tiles red in a single stroke:

Sample Case 1:

Nikita will need 3 strokes to paint all 5 tiles:

Solution: