day2 solution

.gitignore

@@ -1,2 +1,3 @@
 *.beam
 *.dump
+*.swp

day2/Makefile

@@ -0,0 +1,8 @@
+all: day2.beam
+	erl -noshell -s day2 start -s init stop
+
+day2.beam:
+	erlc day2.erl
+
+clean:
+	rm -f day2.beam

day2/day2.erl

@@ -0,0 +1,74 @@
+-module(day2).
+-export([start/0]).
+
+split_string_into_list_of_integers(Input)
+  -> io:fwrite("~s ", [Input]),
+     [ Z || Z <- lists:map(fun(X) -> {Y,_} = string:to_integer(X), Y end, re:split(Input, "\t")), is_integer(Z) ].
+
+split_string_into_rows(Input)
+  -> re:split(Input, "\n").
+
+row_checksum(Row)
+  -> Min = lists:min(Row),
+     Max = lists:max(Row),
+     Difference = Max - Min,
+     io:fwrite("~p ~B~n", [Row, Difference]),
+     Difference.
+
+factor_row_checksum(Row)
+	-> [Factors|_] = [Z || Z <- lists:map(fun(X) -> DifferentFactors = lists:filter(fun(Y) -> X /= Y end, Row),
+																							T = lists:filter(fun(Y) -> (X / Y) == (X div Y) end, DifferentFactors),
+																							if length(T) > 0 -> [U|_] = T, [X,U] ; true -> [] end
+																							end, Row),
+										 length(Z) > 0 ],
+		 io:fwrite("~p~n", [Factors]),
+		 Min = lists:min(Factors),
+		 Max = lists:max(Factors),
+		 Max div Min.
+
+parse_matrix(Input)
+  -> Checksum = lists:foldl(fun(Row, Sum) -> Sum + row_checksum(split_string_into_list_of_integers(Row)) end, 0, split_string_into_rows(Input)),
+     io:fwrite("~B~n", [Checksum]),
+     Checksum.
+
+parse_matrix_factors(Input)
+	-> Checksum = lists:foldl(fun(Row, Sum) -> Sum + factor_row_checksum(split_string_into_list_of_integers(Row)) end, 0, split_string_into_rows(Input)),
+		 io:fwrite("~B~n", [Checksum]),
+		 Checksum.
+
+start()
+  -> parse_matrix("5	1	9	5
+7	5	3
+2	4	6	8"),
+     parse_matrix("116	1259	1045	679	1334	157	277	1217	218	641	1089	136	247	1195	239	834
+269	1751	732	3016	260	6440	5773	4677	306	230	6928	7182	231	2942	2738	3617
+644	128	89	361	530	97	35	604	535	297	599	121	567	106	114	480
+105	408	120	363	430	102	137	283	123	258	19	101	181	477	463	279
+873	116	840	105	285	238	540	22	117	125	699	953	920	106	113	259
+3695	161	186	2188	3611	2802	157	2154	3394	145	2725	1327	3741	2493	3607	4041
+140	1401	110	119	112	1586	125	937	1469	1015	879	1798	122	1151	100	926
+2401	191	219	607	267	2362	932	2283	889	2567	2171	2409	1078	2247	2441	245
+928	1142	957	1155	922	1039	452	285	467	305	506	221	281	59	667	232
+3882	1698	170	5796	2557	173	1228	4630	174	3508	5629	4395	180	5100	2814	2247
+396	311	223	227	340	313	355	469	229	162	107	76	363	132	453	161
+627	1331	1143	1572	966	388	198	2068	201	239	176	1805	1506	1890	1980	1887
+3390	5336	1730	4072	5342	216	3823	85	5408	5774	247	5308	232	256	5214	787
+176	1694	1787	1586	3798	4243	157	4224	3603	2121	3733	851	2493	4136	148	153
+2432	4030	3397	4032	3952	2727	157	3284	3450	3229	4169	3471	4255	155	127	186
+919	615	335	816	138	97	881	790	855	89	451	789	423	108	95	116"),
+		 parse_matrix_factors("116	1259	1045	679	1334	157	277	1217	218	641	1089	136	247	1195	239	834
+269	1751	732	3016	260	6440	5773	4677	306	230	6928	7182	231	2942	2738	3617
+644	128	89	361	530	97	35	604	535	297	599	121	567	106	114	480
+105	408	120	363	430	102	137	283	123	258	19	101	181	477	463	279
+873	116	840	105	285	238	540	22	117	125	699	953	920	106	113	259
+3695	161	186	2188	3611	2802	157	2154	3394	145	2725	1327	3741	2493	3607	4041
+140	1401	110	119	112	1586	125	937	1469	1015	879	1798	122	1151	100	926
+2401	191	219	607	267	2362	932	2283	889	2567	2171	2409	1078	2247	2441	245
+928	1142	957	1155	922	1039	452	285	467	305	506	221	281	59	667	232
+3882	1698	170	5796	2557	173	1228	4630	174	3508	5629	4395	180	5100	2814	2247
+396	311	223	227	340	313	355	469	229	162	107	76	363	132	453	161
+627	1331	1143	1572	966	388	198	2068	201	239	176	1805	1506	1890	1980	1887
+3390	5336	1730	4072	5342	216	3823	85	5408	5774	247	5308	232	256	5214	787
+176	1694	1787	1586	3798	4243	157	4224	3603	2121	3733	851	2493	4136	148	153
+2432	4030	3397	4032	3952	2727	157	3284	3450	3229	4169	3471	4255	155	127	186
+919	615	335	816	138	97	881	790	855	89	451	789	423	108	95	116").