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2559-count-vowel-strings-in-ranges/2559-count-vowel-strings-in-ranges.java

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+class Solution {
+    public int[] vowelStrings(String[] words, int[][] queries) {
+        int arr[] = new int[words.length];
+
+        HashSet<Character> set = new HashSet();
+        set.add('a');
+        set.add('e');
+        set.add('i');
+        set.add('o');
+        set.add('u');
+
+        for (int i = 0; i < words.length; i++){
+            String s = words[i];
+            if (set.contains(s.charAt(0)) && set.contains(s.charAt(s.length() - 1))) arr[i] = i > 0 ? arr[i - 1] + 1 : 1;
+            else arr[i] = i > 0 ? arr[i - 1] : 0;
+        }
+        int ans[] = new int[queries.length];
+        int i = 0;
+        for(int q[] : queries){
+            int l = q[0];
+            int j = q[1];
+            int k = arr[j];
+            k = l == 0 ? k : k - arr[l - 1];
+            ans[i++] = k;
+        }
+        return ans;
+    }
+}