update readme

Author: flixpar

README.md

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 # Quadratic Assignment Problem
 
 Algorithms for (approximately) solving the quadratic assignment problem (QAP) implemented in Julia.
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+Exact algorithms:
+- Quadratic integer programming
+- Linearization
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+Approximation algorithms:
+- "On the Maximum Quadratic Assignment Problem" by Nagarajan and Sviridenko (NS)
+- "Maximum Quadratic Assignment Problem: Reduction from Maximum Label Cover and LP-based Approximation Algorithm" by Makarychev, Manokaran, and Sviridenko (MMS)
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+Heuristic algorithms:
+- Fast Approximate QAP
+- Random search
+- LP + LAP rounding