diff --git a/1358. Number of Substrings Containing All Three Characters b/1358. Number of Substrings Containing All Three Characters
new file mode 100644
index 0000000..0485cc3
--- /dev/null
+++ b/1358. Number of Substrings Containing All Three Characters	
@@ -0,0 +1,18 @@
+class Solution {
+public:
+    int numberOfSubstrings(std::string s) {
+        std::vector<int> count(3, 0); 
+        int left = 0; 
+        int result = 0; 
+        for (int i = 0; i < s.length(); i++) {
+            count[s[i] - 'a']++; 
+
+            while (count[0] > 0 && count[1] > 0 && count[2] > 0) {
+                result += s.length() - i; 
+                count[s[left] - 'a']--; 
+                left++; 
+            }
+        }
+        return result; 
+    }
+};