Data commit

Task/Look-and-say-sequence/SQL/look-and-say-sequence.sql

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+DROP VIEW delta;
+CREATE VIEW delta AS
+    SELECT sequence1.v AS x,
+           (sequence1.v<>sequence2.v)*sequence1.c AS v,
+           sequence1.c AS c
+      FROM sequence AS sequence1,
+           sequence AS sequence2
+     WHERE sequence1.c = sequence2.c+1;
+
+DROP VIEW rle0;
+CREATE VIEW rle0 AS
+    SELECT delta2.x AS x,
+           SUM(delta2.v) AS v,
+           delta2.c AS c
+      FROM delta AS delta1,
+           delta as delta2
+     WHERE delta1.c >= delta2.c
+  GROUP BY delta1.c;
+
+DROP VIEW rle1;
+CREATE VIEW rle1 AS
+    SELECT sum(x)/x AS a,
+           x AS b,
+           c AS c
+      FROM rle0
+  GROUP BY v;
+
+DROP VIEW rle2;
+CREATE VIEW rle2 AS
+    SELECT a as v, 1 as o, 2*c+0 as c FROM rle1 UNION
+    SELECT b as v, 1 as o, 2*c+1 as c FROM rle1;
+
+DROP VIEW normed;
+CREATE VIEW normed AS
+    SELECT r1.v as v, SUM(r2.o) as c
+      FROM rle2 AS r1,
+           rle2 AS r2
+     WHERE r1.c >= r2.c
+  GROUP BY r1.c;
+
+DROP TABLE rle;
+CREATE TABLE rle(v int, c int);
+INSERT INTO rle SELECT * FROM normed ORDER BY c;
+
+DELETE FROM sequence;
+INSERT INTO sequence VALUES(-1,0);
+INSERT INTO sequence SELECT * FROM rle;