xy_balance¶

Requirements:

access a single character
loop through a string (while)
if, elif, else

We’ll say that a String is xy-balanced if for all the 'x' chars in the string, there exists a 'y' char somewhere later in the string. So "xxy" is balanced, but "xyx" is not. One 'y' can balance multiple 'x's. Output True if the given string is xy-balanced. Output False otherwise.

This exercise was taken from codingbat.com and has been adapted for the Python language. There are many great programming exercises there, but the majority are created for Java.

Test 1¶

Input:

'aaxbby'

Output:

True

Test 2¶

Input:

'aaxbb'

Output:

False

Test 3¶

Input:

'yaaxbb'

Output:

False

Test 4¶

Input:

'yaaxbby'

Output:

True

Test 5¶

Input:

'xaxxbby'

Output:

True

Test 6¶

Input:

'xaxxbbyx'

Output:

False

Test 7¶

Input:

'xxbxy'

Output:

True

Test 8¶

Input:

'xxbx'

Output:

False

Test 9¶

Input:

'bbb'

Output:

True

Test 10¶

Input:

'bxbb'

Output:

False

Test 11¶

Input:

'bxyb'

Output:

True

Test 12¶

Input:

'xy'

Output:

True

Test 13¶

Input:

'y'

Output:

True

Test 14¶

Input:

'x'

Output:

False

Test 15¶

Input:

''

Output:

True

Test 16¶

Input:

'yxyxyxyx'

Output:

False

Test 17¶

Input:

'yxyxyxyxy'

Output:

True

Test 18¶

Input:

'12xabxxydxyxyzz'

Output:

True