Added interleaved of strings in C++

c++/InterleavedStrings.cpp

@@ -0,0 +1,87 @@
+// A Dynamic Programming based program to check whether a string str3 is an interleaving of two other strings str1 and str2.
+#include <iostream>
+#include <string.h>
+using namespace std;
+
+bool isInterleaved(
+	char* str1, char* str2, char* str3)
+{
+	// Find lengths of the two strings
+	int lenOfStr1= strlen(str1), lenOfStr2 = strlen(str2);
+
+	bool table[lenOfStr1 + 1][lenOfStr2 + 1];
+
+	// Initialize all values as false.
+	memset(table, 0, sizeof(table));
+
+	if ((lenOfStr1 + lenOfStr2) != strlen(str3))
+		return false;
+
+	// Process all characters of str1 and str2
+	for (int i = 0; i <=lenOfStr1 ; ++i) {
+		for (int j = 0; j <=lenOfStr2 ; ++j) {
+			// two empty strings have an
+			// empty string as interleaving
+			if (i == 0 && j == 0)
+				table[i][j] = true;
+
+			// str1 is empty
+			else if (i == 0) {
+				if (str2[j - 1] == str3[j - 1])
+					table[i][j] = table[i][j - 1];
+			}
+
+			// str2 is empty
+			else if (j == 0) {
+			    if (str1[i - 1] == str3[i - 1])
+					table[i][j] = table[i - 1][j];
+			}
+
+			// Current character of str3 matches
+			// with current character of str1,
+			// but doesn't match with current
+			// character of str2
+			else if (
+				str1[i - 1] == str3[i + j - 1]
+				&& str2[j - 1] != str3[i + j - 1])
+				table[i][j] = table[i - 1][j];
+
+			// Current character of str3 matches
+			// with current character of str2,
+			// but doesn't match with current
+			// character of str1
+			else if (str1[i - 1] != str3[i + j - 1]&& str2[j - 1] == str3[i + j - 1])
+				table[i][j] = table[i][j - 1];
+
+			// Current character of str3 matches
+			// with that of both str1 and str2
+			else if (str1[i - 1] == str3[i + j - 1]&& str2[j - 1] == str3[i + j - 1])
+				table[i][j]= (table[i - 1][j]|| table[i][j - 1]);
+		}
+	}
+
+	return table[lenOfStr1][lenOfStr2];
+}
+
+// A function to run test cases
+void test(char* str1, char* str2, char* str3)
+{
+	if (isInterleaved(str1, str2, str3))
+		cout << str3 << " is interleaved of "
+			<< str1 << " and " << str2 << endl;
+	else
+		cout << str3 << " is not interleaved of "
+			<< str1 << " and " << str2 << endl;
+}
+
+// Driver program to test above functions
+int main()
+{
+	test("XXY", "XXZ", "XXZXXXY");
+	test("XY", "WZ", "WZXY");
+	test("XY", "X", "XXY");
+	test("YX", "X", "XXY");
+	test("XXY", "XXZ", "XXXXZY");
+	return 0;
+}
+// Time complexity of program is O(length of str1 * length of str2)