Solution.java

class Solution {
    public String[] findLongestSubarray(String[] array) {
        Map<Integer, Integer> vis = new HashMap<>();
        vis.put(0, -1);
        int s = 0, mx = 0, k = 0;
        for (int i = 0; i < array.length; ++i) {
            s += array[i].charAt(0) >= 'A' ? 1 : -1;
            if (vis.containsKey(s)) {
                int j = vis.get(s);
                if (mx < i - j) {
                    mx = i - j;
                    k = j + 1;
                }
            } else {
                vis.put(s, i);
            }
        }
        String[] ans = new String[mx];
        System.arraycopy(array, k, ans, 0, mx);
        return ans;
    }
}