Solve 18.1 and 18.2 with rosettacode.org

2021-05-16 20:00:28 +03:00
parent 327631206d
commit f79c4c9263
2 changed files with 500 additions and 0 deletions
@@ -0,0 +1,126 @@
+# http://rosettacode.org/wiki/Parsing/Shunting-yard_algorithm#Python
+# http://rosettacode.org/wiki/Parsing/RPN_calculator_algorithm#Python
+with open("input") as f:
+    data = f.read().strip().split("\n")
+
+
+def calc(s):
+    a=[]
+    b={'+': lambda x,y: y+x, '-': lambda x,y: y-x, '*': lambda x,y: y*x,'/': lambda x,y:y/x,'^': lambda x,y:y**x}
+    for c in s.split():
+        if c in b: a.append(b[c](a.pop(),a.pop()))
+        else: a.append(int(c))
+    return a[0]
+
+from collections import namedtuple
+from pprint import pprint as pp
+ 
+OpInfo = namedtuple('OpInfo', 'prec assoc')
+L, R = 'Left Right'.split()
+ 
+ops = {
+ '^': OpInfo(prec=4, assoc=R),
+ '*': OpInfo(prec=2, assoc=L),
+ '/': OpInfo(prec=3, assoc=L),
+ '+': OpInfo(prec=2, assoc=L),
+ '-': OpInfo(prec=2, assoc=L),
+ '(': OpInfo(prec=9, assoc=L),
+ ')': OpInfo(prec=0, assoc=L),
+ }
+ 
+NUM, LPAREN, RPAREN = 'NUMBER ( )'.split()
+ 
+ 
+def get_input(inp = None):
+    'Inputs an expression and returns list of (TOKENTYPE, tokenvalue)'
+ 
+    if inp is None:
+        inp = input('expression: ')
+    tokens = inp.strip().split()
+    tokenvals = []
+    for token in tokens:
+        if token in ops:
+            tokenvals.append((token, ops[token]))
+        #elif token in (LPAREN, RPAREN):
+        #    tokenvals.append((token, token))
+        else:    
+            tokenvals.append((NUM, token))
+    return tokenvals
+ 
+def shunting(tokenvals):
+    outq, stack = [], []
+    table = ['TOKEN,ACTION,RPN OUTPUT,OP STACK,NOTES'.split(',')]
+    for token, val in tokenvals:
+        note = action = ''
+        if token is NUM:
+            action = 'Add number to output'
+            outq.append(val)
+            table.append( (val, action, ' '.join(outq), ' '.join(s[0] for s in stack), note) )
+        elif token in ops:
+            t1, (p1, a1) = token, val
+            v = t1
+            note = 'Pop ops from stack to output' 
+            while stack:
+                t2, (p2, a2) = stack[-1]
+                if (a1 == L and p1 <= p2) or (a1 == R and p1 < p2):
+                    if t1 != RPAREN:
+                        if t2 != LPAREN:
+                            stack.pop()
+                            action = '(Pop op)'
+                            outq.append(t2)
+                        else:    
+                            break
+                    else:        
+                        if t2 != LPAREN:
+                            stack.pop()
+                            action = '(Pop op)'
+                            outq.append(t2)
+                        else:    
+                            stack.pop()
+                            action = '(Pop & discard "(")'
+                            table.append( (v, action, ' '.join(outq), ' '.join(s[0] for s in stack), note) )
+                            break
+                    table.append( (v, action, ' '.join(outq), ' '.join(s[0] for s in stack), note) )
+                    v = note = ''
+                else:
+                    note = ''
+                    break
+                note = '' 
+            note = '' 
+            if t1 != RPAREN:
+                stack.append((token, val))
+                action = 'Push op token to stack'
+            else:
+                action = 'Discard ")"'
+            table.append( (v, action, ' '.join(outq), ' '.join(s[0] for s in stack), note) )
+    note = 'Drain stack to output'
+    while stack:
+        v = ''
+        t2, (p2, a2) = stack[-1]
+        action = '(Pop op)'
+        stack.pop()
+        outq.append(t2)
+        table.append( (v, action, ' '.join(outq), ' '.join(s[0] for s in stack), note) )
+        v = note = ''
+    return table
+ 
+
+def rpn(s):
+    s = s.replace('(', ' ( ').replace(')', ' ) ')
+    rp = shunting(get_input(s))
+    return rp[-1][2]
+
+
+print(sum(calc(rpn(s)) for s in data))
+
+ops = {
+ '^': OpInfo(prec=4, assoc=R),
+ '*': OpInfo(prec=2, assoc=L),
+ '/': OpInfo(prec=3, assoc=L),
+ '+': OpInfo(prec=3, assoc=L),
+ '-': OpInfo(prec=2, assoc=L),
+ '(': OpInfo(prec=9, assoc=L),
+ ')': OpInfo(prec=0, assoc=L),
+ }
+print(sum(calc(rpn(s)) for s in data))
+