diff --git a/GeeksforGeeks/Algorithm/DP/LongestSubstringWithoutRepeatingCharacters.py b/GeeksforGeeks/Algorithm/DP/LongestSubstringWithoutRepeatingCharacters.py
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index 0000000..dd72213
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+++ b/GeeksforGeeks/Algorithm/DP/LongestSubstringWithoutRepeatingCharacters.py
@@ -0,0 +1,33 @@
+'''
+Given a string S, find the length of its longest substring that does not have any repeating characters.
+
+Example 1:
+
+Input:
+S = geeksforgeeks
+Output: 7
+Explanation: The longest substring
+without repeated characters is "ksforge".
+Example 2:
+
+Input:
+S = abbcdb
+Output: 3
+Explanation: The longest substring is
+"bcd". Here "abcd" is not a substring
+of the given string.
+'''
+
+
+def SubsequenceLength(s):
+    v={}
+    l=0
+    maxlen=0
+    for i in range(len(s)):
+        if s[i] in v and l<=v[s[i]]:
+            l=v[s[i]]+1
+        else:
+            maxlen=max(maxlen,i-l+1)
+        v[s[i]]=i
+    return maxlen
+