fix: add <cstdint> to string/**

Author: realstealthninja

strings/manacher_algorithm.cpp

@@ -11,6 +11,7 @@
  */
 
 #include <cassert>   /// for assert
+#include <cstdint>   /// for integral typedefs
 #include <iostream>  /// for IO operations
 #include <vector>    /// for std::vector STL
 #ifdef _MSC_VER

strings/z_function.cpp

@@ -11,6 +11,7 @@
  * @author [Ritika Gupta](https://github.com/RitikaGupta8734)
  */
 
+#include <cstdint>   /// for integral typedefs
 #include <iostream>  /// for IO operations
 #ifdef _MSC_VER
 #include <string>  /// for string (use this for MS Visual C++)