Problem A. Store Credit.clj

(ns store-credit
  (use [clojure.contrib.str-utils])
  (:import (java.io BufferedReader FileReader)))

(defn sum-items [v i]
	(let [h (first v)
	      r (rest v)
	      j (atom i)]
	      (if (empty? v)
		  []
		  (concat (map #(vector [i (swap! j (fn [n] (inc n)))] (+ h  %1)) r) (sum-items r (inc i))))))

(defn read-file [file-name]
  (with-open [reader (BufferedReader. (FileReader. file-name))]
    (let [lines (line-seq reader)
	  n     (Integer/parseInt (first lines))]
      (doseq [[xs i] (map vector (partition 3 (rest lines)) (range 1 (inc n)))]
	(let [c  (Integer/parseInt (first xs))
	      l  (second xs)
	      ps (vec (re-split #"\s+" ((comp first rest rest) xs)))
	      s  (sum-items (map #(Integer/parseInt %1) ps) 0)
	      idx (first (filter #(= (second %1) c) s))
	      pair (map inc (first idx))]
	  (println (str "Case #" i ":") (first pair) (second pair)))))))