You are given a string s consisting of digits. Perform the following operation repeatedly until the string has exactly two digits:
s, starting from the first digit, calculate a new digit as the sum of the two digits modulo 10.s with the sequence of newly calculated digits, maintaining the order in which they are computed.Return true if the final two digits in s are the same; otherwise, return false.
Example 1:
Input: s = "3902"
Output: true
Explanation:
s = "3902"(s[0] + s[1]) % 10 = (3 + 9) % 10 = 2(s[1] + s[2]) % 10 = (9 + 0) % 10 = 9(s[2] + s[3]) % 10 = (0 + 2) % 10 = 2s becomes "292"(s[0] + s[1]) % 10 = (2 + 9) % 10 = 1(s[1] + s[2]) % 10 = (9 + 2) % 10 = 1s becomes "11""11" are the same, the output is true.Example 2:
Input: s = "34789"
Output: false
Explanation:
s = "34789".s = "7157".s = "862".s = "48".'4' != '8', the output is false.
Constraints:
3 <= s.length <= 100s consists of only digits.class Solution {
public boolean hasSameDigits(String s) {
StringBuilder sb = new StringBuilder(s);
int n = sb.length();
while (n > 2) {
s = sb.toString();
sb.setLength(0);
for (int i = 0; i < n - 1; i++)
sb.append((s.charAt(i) + s.charAt(i + 1) - 2 * '0') % 10);
n = sb.length();
// System.out.println(sb);
}
return sb.charAt(0) == sb.charAt(1);
}
}