Merge pull request #100 from ritikpatel17/patch-4

 Substring with Concatenation of All Words

check.java

@@ -0,0 +1,97 @@
+class Solution {
+    private HashMap<String, Integer> wordCount = new HashMap<String, Integer>();
+    private int wordLength;
+    private int substringSize;
+    private int k;
+
+    private boolean check(int i, String s) {
+        // Copy the original dictionary to use for this index
+        HashMap<String, Integer> remaining = new HashMap<>(wordCount);
+        int wordsUsed = 0;
+
+        // Each iteration will check for a match in words
+        for (int j = i; j < i + substringSize; j += wordLength) {
+            String sub = s.substring(j, j + wordLength);
+            if (remaining.getOrDefault(sub, 0) != 0) {
+                remaining.put(sub, remaining.get(sub) - 1);
+                wordsUsed++;
+            } else {
+                break;
+            }
+        }
+
+        return wordsUsed == k;
+    }
+
+    public List<Integer> findSubstring(String s, String[] words) {
+        int n = s.length();
+        k = words.length;
+        wordLength = words[0].length();
+        substringSize = wordLength * k;
+
+        for (String word : words) {
+            wordCount.put(word, wordCount.getOrDefault(word, 0) + 1);
+        }
+
+        List<Integer> answer = new ArrayList<>();
+        for (int i = 0; i < n - substringSize + 1; i++) {
+            if (check(i, s)) {
+                answer.add(i);
+            }
+        }
+
+        return answer;
+    }
+}
+
+// class Solution {
+//     public List<Integer> findSubstring(String s, String[] words) {
+//         List<Integer> lst = new LinkedList();
+//         for(int i=0; i<s.length(); i+=4){
+//             int x = Check(s,words, i);
+//             if(x!=-1){
+//                 lst.add(x);
+//             }
+//         }
+//         return lst;
+
+//     }
+//     int Check(String s,String[] words, int index){
+//         HashMap <String, Integer> map = new HashMap();
+//         for(int i=0; i<words.length; i++) {
+//             if(map.containsKey(words[i])){
+//                 int x = map.get(words[i]);
+//                 x++;
+//                 map.put(words[i],x);
+//             }
+//             else{
+//                 map.put(words[i],1);
+//             }
+//         }
+//         int i=0;
+//         while(i<words.length*words[0].length()){
+//             String str = "";
+//             int j=0;
+//             while(j<4&&i<words.length){
+//                 str+=s.charAt(i+index);
+//                 i++;
+//                 j++;
+//             }
+//             if(map.containsKey(str)){
+//                 int x = map.get(str);
+//                 x--;
+//                 if(x==0){
+//                     map.remove(str);
+//                 }
+//             }
+//             if(map.size()==0){
+//                 return i+index-words.length*words[0].length();
+
+//             }
+
+//         }
+//         return -1;
+
+//     }
+
+// }