3306_Count_of_Substrings_containing_every_single_vowel_and_k_consoneants_II.java

Author: vishwajeetmishra4

JAVA/3306_Count_of_Substrings_containing_every_single_vowel_and_k_consoneants_II.java

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+// Problem Number 3306
+
+// Count of Substrings containing every single vowel and K consonants II
+
+class Solution {
+  public long countOfSubstrings(String word, int k) {
+    return substringsWithAtMost(word, k) - substringsWithAtMost(word, k - 1);
+  }
+
+  private long substringsWithAtMost(String word, int k) {
+    if (k == -1)
+      return 0;
+
+    long res = 0;
+    int vowels = 0;
+    int uniqueVowels = 0;
+    Map<Character, Integer> vowelLastSeen = new HashMap<>();
+
+    for (int l = 0, r = 0; r < word.length(); ++r) {
+      if (isVowel(word.charAt(r))) {
+        ++vowels;
+        if (!vowelLastSeen.containsKey(word.charAt(r)) || vowelLastSeen.get(word.charAt(r)) < l)
+          ++uniqueVowels;
+        vowelLastSeen.put(word.charAt(r), r);
+      }
+      while (r - l + 1 - vowels > k) {
+        if (isVowel(word.charAt(l))) {
+          --vowels;
+          if (vowelLastSeen.get(word.charAt(l)) == l)
+            --uniqueVowels;
+        }
+        ++l;
+      }
+      if (uniqueVowels == 5) {
+        final int minVowelLastSeen = Arrays.asList('a', 'e', 'i', 'o', 'u')
+         .stream()
+         .mapToInt(vowel -> vowelLastSeen.get(vowel))
+         .min()
+         .getAsInt();
+        res += minVowelLastSeen - l + 1;
+      }
+    }
+
+    return res;
+  }
+
+  private boolean isVowel(char c) {
+    return "aeiou".indexOf(c) != -1;
+  }
+}