Package g2901_3000.s2938_separate_black_and_white_balls

Class Solution

java.lang.Object
g2901_3000.s2938_separate_black_and_white_balls.Solution
public class Solution extends java.lang.Object
2938 - Separate Black and White Balls.

Medium

There are n balls on a table, each ball has a color black or white.

You are given a 0-indexed binary string s of length n, where 1 and 0 represent black and white balls, respectively.

In each step, you can choose two adjacent balls and swap them.

Return the minimum number of steps to group all the black balls to the right and all the white balls to the left.

Example 1:

Input: s = “101”

Output: 1

Explanation: We can group all the black balls to the right in the following way:

  • Swap s[0] and s[1], s = “011”.

Initially, 1s are not grouped together, requiring at least 1 step to group them to the right.

Example 2:

Input: s = “100”

Output: 2

Explanation: We can group all the black balls to the right in the following way:

  • Swap s[0] and s[1], s = “010”.
  • Swap s[1] and s[2], s = “001”.

It can be proven that the minimum number of steps needed is 2.

Example 3:

Input: s = “0111”

Output: 0

Explanation: All the black balls are already grouped to the right.

Constraints:

  • 1 <= n == s.length <= 105
  • s[i] is either '0' or '1'.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    long
    minimumSteps(java.lang.String s)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • minimumSteps

      public long minimumSteps(java.lang.String s)