Create 1698.Number-of-Distinct-Substrings-in-a-String_v2.cpp

String/1698.Number-of-Distinct-Substrings-in-a-String/1698.Number-of-Distinct-Substrings-in-a-String_v2.cpp

@@ -0,0 +1,29 @@
+class Solution {
+public:
+    int countDistinct(string s) 
+    {
+        int n = s.size();
+        long base = 26;
+        long M = 1e9+9;
+        int count = 1;
+        long power = 1;
+        long hash0 = 0;
+
+        for (int len = 1; len <=n-1; len++)
+        {            
+            hash0 = (hash0 * base % M + s[len-1]-'a') % M;            
+            power = (power * base) % M;
+
+            unordered_set<long>Set({hash0});
+            long hash = hash0;            
+            for (int i=len; i<n; i++)
+            {
+                hash = (hash * base % M + (s[i]-'a')) % M; 
+                hash = (hash - power*(s[i-len]-'a') % M + M) %M ;
+                Set.insert(hash);
+            }
+            count += Set.size();
+        }
+        return count;        
+    }
+};