Merge pull request #578 from talk2sourajit/patch-1

Create Longest_Substring.cpp

Author: Sirajmolla

Longest_Substring.cpp

@@ -0,0 +1,41 @@
+// C++ program to find the length of the longest substring
+// without repeating characters
+#include <bits/stdc++.h>
+using namespace std;
+// This function returns true if all characters in str[i..j]
+// are distinct, otherwise returns false
+bool areDistinct(string str, int i, int j)
+{
+	vector<bool> visited(26);
+	for (int k = i; k <= j; k++) {
+		if (visited[str[k] - 'a'] == true)
+			return false;
+		visited[str[k] - 'a'] = true;
+	}
+	return true;
+}
+
+// Returns length of the longest substring
+// with all distinct characters.
+int longestUniqueSubsttr(string str)
+{
+	int n = str.size();
+	int res = 0; // result
+	for (int i = 0; i < n; i++)
+		for (int j = i; j < n; j++)
+			if (areDistinct(str, i, j))
+				res = max(res, j - i + 1);
+	return res;
+}
+
+// Driver code
+int main()
+{
+	string str = "bobisbobbydeol";
+	cout << "The input string is " << str << endl;
+	int len = longestUniqueSubsttr(str);
+	cout << "The length of the longest non-repeating "
+			"character substring is "
+		<< len;
+	return 0;
+}