Question

You are given a string S consisting of N lowercase English letters. In how many ways can we split S into two non-empty parts, such that in at least one part the letter 'x' and the letter 'y' occur the same number of times? Write a function: int solution(string &s); that, given a string S of length N, returns the number of splits S satisfying the condition above.

Answer 1

To solve this problem, we can count the occurrences of 'x' and 'y' in the string and check all possible split points. By considering all possible split positions and counting the occurrences of 'x' and 'y' in each part, we can accurately calculate the number of splits that satisfy the condition.

Step-by-step explanation:

One way to approach this problem is by counting the number of occurrences of 'x' and 'y' in the string and checking all possible split points. Let's assume that 'x' occurs n_x times and 'y' occurs n_y times in the string.

For the split to satisfy the condition, one part must have the same number of 'x' and 'y' occurrences. We can consider all possible split positions and count the number of occurrences of 'x' and 'y' in each part. If the counts are the same, we increment our counter.

We can iterate through all possible split positions from 1 to N-1 and check the counts using a prefix sum to calculate the counts efficiently.