Adding solution for Day 22 Challenge Problem (codedecks-in#176)

Co-authored-by: Priyanka Suthaar <priyanka94suthaar@gmail.com>

Author: Priyanka94suthaar

Java/June-LeetCoding-Challenge/Day22StrSubsequenceCount.java

@@ -0,0 +1,41 @@
+import java.util.*;
+
+public class Day22StrSubsequenceCount {
+ public static void main(String[] args){
+ String str = "abacde";
+ String[] words = {"a", "bb", "acd", "ace"};
+ int count = numMatchingSequence(str,words);
+ System.out.println(count);
+ }
+
+ public static int numMatchingSequence(String str, String[] words){
+ int result = 0;
+ Map<Character, List<Integer>> map = new HashMap<>();
+
+ for(int i=0; i<str.length(); i++){
+ map.putIfAbsent(str.charAt(i), new ArrayList<>());
+ map.get(str.charAt(i)).add(i); // It will add size of that character in map (occurence)
+ }
+
+ for (String word : words) {
+ if (match(str, word, map, 0)) {
+ result++;
+ }
+ }
+
+ return result;
+ }
+
+ private static boolean match(String S, String word, Map<Character, List<Integer>> map, int startIndex) {
+ if (word.length() == 0) return true;
+ if (!map.containsKey(word.charAt(0))) return false;
+ for (int start : map.get(word.charAt(0))) {
+ if (start < startIndex) continue;
+ String newWord = word.substring(1, word.length());
+ return match(S, newWord, map, start + 1);
+ }
+
+ return false;
+ }
+
+}