Description

This is an attempt to solve this problem: https://codeforces.com/problemset/problem/1902/A

The Main.java file was successfully submitted to codeforces without the package statement.

Rationale of implementation

The outcome of the insert operation relies on the values of current and next characters. The four cases are:

• 00 -> 010
• 01 -> 001
• 10 -> 100
• 11 -> 111

Since we want to have more zeroes than ones, we are only interested in inserting zeroes, which means patterns 01 and 10 are interesting for us. Please note that, for both patterns, we can repeat the insert operation as many times as we want so that we have more zeroes than ones at the end.

We are left with the following cases:

• If the string only have ones, we cannot insert zeroes. Answer is NO.
• If the string contains at least one zero, either it is 0: answer is YES, or it contains patterns 01 or 10. We repeat the insert operation until we have enough zeroes.

Therefore, answer is YES if and only if input string contains at least one 0 character.