public class Solution
extends Object
1573 - Number of Ways to Split a String\.
Medium
Given a binary string `s`, you can split `s` into 3 **non-empty** strings `s1`, `s2`, and `s3` where `s1 + s2 + s3 = s`.
Return the number of ways `s` can be split such that the number of ones is the same in `s1`, `s2`, and `s3`. Since the answer may be too large, return it **modulo** 109 + 7.
**Example 1:**
**Input:** s = "10101"
**Output:** 4
**Explanation:** There are four ways to split s in 3 parts where each part contain the same number of letters '1'.
"1|010|1"
"1|01|01"
"10|10|1"
"10|1|01"
**Example 2:**
**Input:** s = "1001"
**Output:** 0
**Example 3:**
**Input:** s = "0000"
**Output:** 3
**Explanation:** There are three ways to split s in 3 parts.
"0|0|00"
"0|00|0"
"00|0|0"
**Constraints:**
* 3 <= s.length <= 105
* `s[i]` is either `'0'` or `'1'`.