You are given a string containing only 4 kinds of characters 'Q',
'W', 'E'
and 'R'
.
A string is said to be balanced if each of its characters
appears n/4
times where n
is the length of the string.
Return the minimum length of the substring that can be replaced with any
other string of the same length to make the original string s
balanced.
Return 0 if the string is already balanced.
Example 1:
Input: s = "QWER" Output: 0 Explanation: s is already balanced.
Example 2:
Input: s = "QQWE" Output: 1 Explanation: We need to replace a 'Q' to 'R', so that "RQWE" (or "QRWE") is balanced.
Example 3:
Input: s = "QQQW" Output: 2 Explanation: We can replace the first "QQ" to "ER".
Example 4:
Input: s = "QQQQ" Output: 3 Explanation: We can replace the last 3 'Q' to make s = "QWER".
Constraints:
1 <= s.length <= 10^5
s.length
is a multiple of 4
s
contains only 'Q'
, 'W'
,
'E'
and 'R'
.