Create Count Vowel Substrings of a String.java

varunu28 · web-flow · commit cca4b898c65c · 2021-11-07T03:11:49.000-08:00
diff --git a/Easy/Count Vowel Substrings of a String.java b/Easy/Count Vowel Substrings of a String.java
@@ -0,0 +1,32 @@
+class Solution {
+  public int countVowelSubstrings(String word) {
+    return atMostVowel(word, 5) - atMostVowel(word, 4);
+  }
+
+  private int atMostVowel(String word, int atMostGoal) {
+    int start = 0;
+    int count = 0;
+    int n = word.length();
+    Map<Character, Integer> map = new HashMap<>();
+    for (int end = 0; end < n; end++) {
+      if (!isVowel(word.charAt(end))) {
+        map.clear();
+        start = end + 1;
+      } else {
+        map.put(word.charAt(end), map.getOrDefault(word.charAt(end), 0) + 1);
+        for (; map.size() > atMostGoal; start++) {
+          map.put(word.charAt(start), map.get(word.charAt(start)) - 1);
+          if (map.get(word.charAt(start)) == 0) {
+            map.remove(word.charAt(start));
+          }
+        }
+        count += end - start + 1;
+      }
+    }
+    return count;
+  }
+  
+  private boolean isVowel(char c) {
+    return "aeiou".indexOf(c) != -1;
+  }
+}
