Data commit

Task/Balanced-ternary/11l/balanced-ternary.11l

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+T BalancedTernary
+   . -:str2dig = [‘+’ = 1, ‘-’ = -1, ‘0’ = 0]
+   . -:dig2str = [1 = ‘+’, -1 = ‘-’, 0 = ‘0’]
+   . -:table = [(0, -1), (1, -1), (-1, 0), (0, 0), (1, 0), (-1, 1), (0, 1)]
+
+   [Int] digits
+
+   F (inp)
+      I all(inp.map(d -> d C (0, 1, -1)))
+         .digits = copy(inp)
+      E
+         X ValueError(‘BalancedTernary: Wrong input digits.’)
+
+   F :from_str(inp)
+      R BalancedTernary(reversed(inp).map(c -> .:str2dig[c]))
+
+   . F :int2ternary(n)
+      I n == 0
+         R [Int]()
+      V n3 = ((n % 3) + 3) % 3
+      I n3 == 0 {R  [0] [+] .:int2ternary(n -I/ 3)}
+      I n3 == 1 {R  [1] [+] .:int2ternary(n -I/ 3)}
+      I n3 == 2 {R [-1] [+] .:int2ternary((n + 1) -I/ 3)}
+      X RuntimeError(‘’)
+
+   F :from_int(inp)
+      R BalancedTernary(.:int2ternary(inp))
+
+   F to_int()
+      R reversed(.digits).reduce(0, (y, x) -> x + 3 * y)
+
+   F String()
+      I .digits.empty
+         R ‘0’
+      R reversed(.digits).map(d -> .:dig2str[d]).join(‘’)
+
+   . F :neg(digs)
+      R digs.map(d -> -d)
+
+   F -()
+      R BalancedTernary(.:neg(.digits))
+
+   . F :add(a, b, =c = 0)
+      I !(!a.empty & !b.empty)
+         I c == 0
+            R I !a.empty {a} E b
+         E
+            R .:add([c], I !a.empty {a} E b)
+      E
+         (V d, c) = .:table[3 + (I !a.empty {a[0]} E 0) + (I !b.empty {b[0]} E 0) + c]
+         V res = .:add(a[1..], b[1..], c)
+         I !res.empty | d != 0
+            R [d] [+] res
+         E
+            R res
+
+   F +(b)
+      R BalancedTernary(.:add(.digits, b.digits))
+
+   F -(b)
+      R (.) + (-b)
+
+   F *(b)
+      F _mul([Int] a, b) -> [Int]
+         I !(!a.empty & !b.empty)
+            R [Int]()
+         E
+            [Int] x
+            I   a[0] == -1 {x = .:neg(b)}
+            E I a[0] ==  0 {}
+            E I a[0] ==  1 {x = b}
+            E
+               assert(0B)
+            V y = [0] [+] @_mul(a[1..], b)
+            R .:add(x, y)
+
+      R BalancedTernary(_mul(.digits, b.digits))
+
+V a = BalancedTernary.from_str(‘+-0++0+’)
+print(‘a: ’a.to_int()‘ ’a)
+
+V b = BalancedTernary.from_int(-436)
+print(‘b: ’b.to_int()‘ ’b)
+
+V c = BalancedTernary.from_str(‘+-++-’)
+print(‘c: ’c.to_int()‘ ’c)
+
+V r = a * (b - c)
+print(‘a * (b - c): ’r.to_int()‘ ’r)