longest substring with non repeating chars

Author: dheeraj9198

src/dymanicProgramming/AllPermutationsOfString.java

@@ -52,7 +52,7 @@ private String permute(char start,String string,int index){
 
 
     public static void main(String[] args) {
-        Permute permute = new Permute("ABC");
+        Permute permute = new Permute("ABCD");
         permute.printAll();
     }
 }

src/dymanicProgramming/LongestSubstringWithoutRepChars.java

@@ -0,0 +1,57 @@
+package dymanicProgramming;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map.Entry;
+
+/**
+ * Created by dheeraj on 7/14/2016.
+ * Length of the longest substring without repeating characters
+ * the longest substrings without repeating characters for “ABDEFGABEF” are “BDEFGA” and “DEFGAB”, with length 6.
+ */
+public class LongestSubstringWithoutRepChars {
+
+
+    public static void main(String[] ss) {
+        String s = "ABDEFGABEF";
+        int start = 0;
+        int length = 1;
+
+        int[] map = new int[256];
+
+        List<String> strings1 = new ArrayList<String>();
+        map[s.charAt(0)]=0;
+        for (int k = 1; k < s.length(); k++) {
+            if (map[s.charAt(k)]< k && map[s.charAt(k)] > start) {
+                if (k - start >= length) {
+                    length = k - start;
+                    Iterator<String> stringIterator = strings1.iterator();
+                    while(stringIterator.hasNext()){
+                        String s1 = stringIterator.next();
+                        if(s1.length() < length){
+                            stringIterator.remove();
+                        }
+                    }
+                    strings1.add(s.substring(start, k));
+                }
+                int num = map[s.charAt(k)];
+                start = num + 1;
+            }
+            map[s.charAt(k)]=k;
+        }
+        if (s.length() - start >= length) {
+            length = s.length() - start;
+            Iterator<String> stringIterator = strings1.iterator();
+            while(stringIterator.hasNext()){
+                String s1 = stringIterator.next();
+                if(s1.length() < length){
+                    stringIterator.remove();
+                }
+            }
+            strings1.add(s.substring(start, s.length()));
+        }
+        System.out.print(strings1);
+    }
+}

src/dymanicProgramming/LongestSubstringWithoutRepCharsAmazonSol.java

@@ -0,0 +1,60 @@
+package dymanicProgramming;
+
+import java.util.*;
+import java.util.Map.Entry;
+
+/**
+ * Created by dheeraj on 7/14/2016.
+ * Length of the longest substring without repeating characters
+ * the longest substrings without repeating characters for “ABDEFGABEF” are “BDEFGA” and “DEFGAB”, with length 6.
+ */
+public class LongestSubstringWithoutRepCharsAmazonSol {
+
+
+    public static void main(String[] ss) {
+        String s = "ABDEFGABE98765432F123";
+        int start = 0;
+        int length = 1;
+
+        HashMap<Character, Integer> characterIntegerHashMap = new HashMap<Character, Integer>();
+        List<String> strings1 = new ArrayList<String>();
+        characterIntegerHashMap.put(s.charAt(0), 0);
+        for (int k = 1; k < s.length(); k++) {
+            if (characterIntegerHashMap.containsKey(s.charAt(k))) {
+                if (k - start >= length) {
+                    length = k - start;
+                    Iterator<String> stringIterator = strings1.iterator();
+                    while(stringIterator.hasNext()){
+                        String s1 = stringIterator.next();
+                        if(s1.length() < length){
+                            stringIterator.remove();
+                        }
+                    }
+                    strings1.add(s.substring(start, k));
+                }
+                int num = characterIntegerHashMap.get(s.charAt(k));
+                start = num + 1;
+                Iterator<Entry<Character, Integer>> iter = characterIntegerHashMap.entrySet().iterator();
+                while (iter.hasNext()) {
+                    Map.Entry<Character, Integer> entry = iter.next();
+                    if (entry.getValue() <= num) {
+                        iter.remove();
+                    }
+                }
+            }
+            characterIntegerHashMap.put(s.charAt(k), k);
+        }
+        if (s.length() - start >= length) {
+            length = s.length() - start;
+            Iterator<String> stringIterator = strings1.iterator();
+            while(stringIterator.hasNext()){
+                String s1 = stringIterator.next();
+                if(s1.length() < length){
+                    stringIterator.remove();
+                }
+            }
+            strings1.add(s.substring(start, s.length()));
+        }
+        System.out.print(strings1);
+    }
+}