(defn havel-hakimi [xs]
  (loop [ys xs]
    (cond (empty? ys) true
          (odd? (reduce + ys)) false
          :else (recur (->> (repeat (- (count ys) (first ys) 1) 0)
                            (concat (repeat (first ys) 1))
                            (map - (rest ys))
                            (remove #{0})
                            sort)))))

#'user/havel-hakimi

(havel-hakimi [3 3 3 3])
(havel-hakimi [1 2 3 4])

true
false

(havel-hakimi [1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 4 4 4 4 5 5 6])

true

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[2019-05-01] An Implementation of Ford-Fulkerson Algorithm in Clojure

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[2018-02-28] Irreducible Dyck Words

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[2016-06-01] Conjugate Partitions

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[2016-04-24] Using Word2Vec from Common Lisp

[2016-04-18] A Migration Analysis

[2016-04-11] Basic Data Analysis with CL without Frameworks

[2016-03-25] Parallel map-reduce in Common Lisp

[2016-02-22] Text Summarization and Topic Analysis

[2016-01-27] Set Covering Problem

[2016-01-25] Kolmogorov-Smirnov Test

[2016-01-20] Eigen-values of the Laplacian and Connected Components of a Graph

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[2015-05-03] Happy Numbers

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[2015-04-05] Hamming Derivative of Hashing Functions

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[2015-02-04] Collatz-type Conjectures (Continued)

[2015-01-31] Collatz-type Conjectures (Continued)

[2015-01-30] Collatz-type Conjectures

[2015-01-28] Experiments with Infinite Recursive Sequences (continued)

[2015-01-17] Experiments with Infinite Recursive Sequences

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