Added Advanced Graph and String Algorithms (Dijkstra, Prim’s, Kruskal’s, Floyd–Warshall, KMP, Rabin–Karp)

[h-banerjee]

This PR adds implementations and explanations for several advanced algorithms in both Graph Theory and String Matching.

Algorithms Added

Graph Algorithms:

Dijkstra’s Shortest Path Algorithm

Prim’s Minimum Spanning Tree

Kruskal’s Minimum Spanning Tree

Floyd–Warshall All-Pairs Shortest Path

String Algorithms:

Knuth–Morris–Pratt (KMP) Pattern Matching

Rabin–Karp String Search

Features

Clean, modular, and well-commented code

Each algorithm includes input/output examples

Time and space complexity documented in comments