[Swift]LeetCode770.基本计算器IV|BasicCalculatorIV

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Given an expression such as expression = "e + 8 - a + 5" and an evaluation map such as {"e": 1} (given in terms of evalvars = ["e"] and evalints = [1]), return a list of tokens representing the simplified expression, such as ["-1*a","14"]

An expression alternates chunks and symbols, with a space separating each chunk and symbol.
A chunk is either an expression in parentheses, a variable, or a non-negative integer.
A variable is a string of lowercase letters (not including digits.) Note that variables can be multiple letters, and note that variables never have a leading coefficient or unary operator like "2x" or "-x".

Expressions are evaluated in the usual order: brackets first, then multiplication, then addition and subtraction. For example, expression = "1 + 2 * 3" has an answer of ["7"].

The format of the output is as follows:

For each term of free variables with non-zero coefficient, we write the free variables within a term in sorted order lexicographically. For example, we would never write a term like "b*a*c", only "a*b*c".
Terms have degree equal to the number of free variables being multiplied, counting multiplicity. (For example, "a*a*b*c" has degree 4.) We write the largest degree terms of our answer first, breaking ties by lexicographic order ignoring the leading coefficient of the term.
The leading coefficient of the term is placed directly to the left with an asterisk separating it from the variables (if they exist.) A leading coefficient of 1 is still printed.
An example of a well formatted answer is ["-2*a*a*a", "3*a*a*b", "3*b*b", "4*a", "5*c", "-6"]
Terms (including constant terms) with coefficient 0 are not included. For example, an expression of "0" has an output of [].

Examples:

Input: expression = "e + 8 - a + 5", evalvars = ["e"], evalints = [1]
Output: ["-1*a","14"]

Input: expression = "e - 8 + temperature - pressure",
evalvars = ["e", "temperature"], evalints = [1, 12]
Output: ["-1*pressure","5"]

Input: expression = "(e + 8) * (e - 8)", evalvars = [], evalints = []
Output: ["1*e*e","-64"]

Input: expression = "7 - 7", evalvars = [], evalints = []
Output: []

Input: expression = "a * b * c + b * a * c * 4", evalvars = [], evalints = []
Output: ["5*a*b*c"]

Input: expression = "((a - b) * (b - c) + (c - a)) * ((a - b) + (b - c) * (c - a))",
evalvars = [], evalints = []
Output: ["-1*a*a*b*b","2*a*a*b*c","-1*a*a*c*c","1*a*b*b*b","-1*a*b*b*c","-1*a*b*c*c","1*a*c*c*c","-1*b*b*b*c","2*b*b*c*c","-1*b*c*c*c","2*a*a*b","-2*a*a*c","-2*a*b*b","2*a*c*c","1*b*b*b","-1*b*b*c","1*b*c*c","-1*c*c*c","-1*a*a","1*a*b","1*a*c","-1*b*c"]

Note:

expression will have length in range [1, 250].
evalvars, evalints will have equal lengths in range [0, 100].

给定一个表达式 expression 如 expression = "e + 8 - a + 5" 和一个求值映射，如 {"e": 1}（给定的形式为 evalvars = ["e"] 和 evalints = [1]），返回表示简化表达式的标记列表，例如 ["-1*a","14"]

表达式交替使用块和符号，每个块和符号之间有一个空格。
块要么是括号中的表达式，要么是变量，要么是非负整数。
块是括号中的表达式，变量或非负整数。
变量是一个由小写字母组成的字符串（不包括数字）。请注意，变量可以是多个字母，并注意变量从不具有像 "2x" 或 "-x" 这样的前导系数或一元运算符。

表达式按通常顺序进行求值：先是括号，然后求乘法，再计算加法和减法。例如，expression = "1 + 2 * 3" 的答案是 ["7"]。

输出格式如下：

对于系数非零的每个自变量项，我们按字典排序的顺序将自变量写在一个项中。例如，我们永远不会写像 “b*a*c” 这样的项，只写 “a*b*c”。
项的次数等于被乘的自变量的数目，并计算重复项。(例如，"a*a*b*c" 的次数为 4。)。我们先写出答案的最大次数项，用字典顺序打破关系，此时忽略词的前导系数。
项的前导系数直接放在左边，用星号将它与变量分隔开(如果存在的话)。前导系数 1 仍然要打印出来。
格式良好的一个示例答案是 ["-2*a*a*a", "3*a*a*b", "3*b*b", "4*a", "5*c", "-6"] 。
系数为 0 的项（包括常数项）不包括在内。例如，“0” 的表达式输出为 []。

示例：

输入：expression = "e + 8 - a + 5", evalvars = ["e"], evalints = [1]
输出：["-1*a","14"]

输入：expression = "e - 8 + temperature - pressure",
evalvars = ["e", "temperature"], evalints = [1, 12]
输出：["-1*pressure","5"]

输入：expression = "(e + 8) * (e - 8)", evalvars = [], evalints = []
输出：["1*e*e","-64"]

输入：expression = "7 - 7", evalvars = [], evalints = []
输出：[]

输入：expression = "a * b * c + b * a * c * 4", evalvars = [], evalints = []
输出：["5*a*b*c"]

输入：expression = "((a - b) * (b - c) + (c - a)) * ((a - b) + (b - c) * (c - a))",
evalvars = [], evalints = []
输出：["-1*a*a*b*b","2*a*a*b*c","-1*a*a*c*c","1*a*b*b*b","-1*a*b*b*c","-1*a*b*c*c","1*a*c*c*c","-1*b*b*b*c","2*b*b*c*c","-1*b*c*c*c","2*a*a*b","-2*a*a*c","-2*a*b*b","2*a*c*c","1*b*b*b","-1*b*b*c","1*b*c*c","-1*c*c*c","-1*a*a","1*a*b","1*a*c","-1*b*c"]

提示：

expression 的长度在 [1, 250] 范围内。
evalvars, evalints 在范围 [0, 100] 内，且长度相同。

同样的测试用例。

使用【测试用例】单独执行，执行正确。

input

"(e + 8) * (e - 8)"
[]
[]

Output

["1*e*e","-64"]

Expected

["1*e*e","-64"]

但是提交时，提示解答错误。问题不大。

Input

"(e + 8) * (e - 8)"
[]
[]

Output

["-63"]

Expected

["1*e*e","-64"]

  1 class Solution {
  2     //evaluation map
  3     static var map:[String:Int] = [String:Int]()   
  4     
  5     func basicCalculatorIV(_ expression: String, _ evalvars: [String], _ evalints: [Int]) -> [String] {
  6         for i in 0..<evalvars.count
  7         {
  8             Solution.map[evalvars[i]] = evalints[i]            
  9         }
 10         var i:Int = 0
 11         var l:Int = expression.count
 12         var stack:[Expression] = [Expression]()
 13         var priStack:[Int] = [Int]()
 14         var zero:Expression = Expression(0)
 15         stack.append(zero)
 16         priStack.append(0)
 17         var pri:Int = 0
 18         
 19         while (i < l)
 20         {
 21             var ch:Character = expression[i]
 22             if ch.isDigit()
 23             {
 24                 var num:Int = 0
 25                 while (i < l && expression[i].isDigit())
 26                 {
 27                     num = num * 10 + (expression[i].ascii - 48)
 28                     i += 1
 29                 }
 30                 stack.append(Expression(num))
 31                 continue
 32             }
 33             if ch.isLetter()
 34             {
 35                 var s:String = String()
 36                 while (i < l && expression[i].isLetter())
 37                 {
 38                     s.append(expression[i])
 39                     i += 1             
 40                 }
 41                 stack.append(Expression(s))
 42                 continue
 43             }
 44             if ch == "(" {pri += 2}
 45             if ch == ")" {pri -= 2}
 46             if ch == "+" || ch == "-" || ch == "*"
 47             {
 48                 var nowPri:Int = pri
 49                 if ch == "*" {nowPri += 1}
 50                 while (!priStack.isEmpty && nowPri <= priStack.last!)
 51                 {
 52                     var now:Expression = stack.removeLast()
 53                     var last:Expression = stack.removeLast()
 54                     priStack.removeLast()
 55                     stack.append(last.cal(now))      
 56                 }
 57                 stack[stack.count - 1].oper = ch
 58                 priStack.append(nowPri)           
 59             }   
 60             i += 1   
 61         }
 62         
 63         while (stack.count > 1)
 64         {
 65             var now:Expression = stack.removeLast()
 66             var last:Expression = stack.removeLast()
 67             stack.append(last.cal(now)) 
 68         }
 69         
 70         return stack.last!.toList()
 71     }
 72 }
 73 
 74 class Term
 75 {
 76     //the parameter of this term
 77     var para:Int = 1
 78     //each factor (e.a. a*b*b*c->{a,b,b,c})    
 79     var arr:[String] = [String]()       
 80     
 81     init(_ x:Int)
 82     {
 83         self.para = x
 84     }
 85     
 86     init(_ s:String)
 87     {
 88         if Solution.map[s] == nil
 89         {
 90             arr.append(s)
 91         }
 92         else
 93         {
 94             para = Solution.map[s]!
 95         }
 96     }
 97     
 98     init(_ that:Term)
 99     {
100         self.para = that.para
101         self.arr = that.arr     
102     }
103     
104     func toString() -> String
105     {
106         if para == 0 {return String()}
107         var ans:String = String()
108         for s in arr
109         {
110             ans += ("*" + s)
111         }
112         return String(para) + ans
113     }  
114     
115     func equals(_ that:Term) -> Bool
116     {
117         if self.arr.count != that.arr.count
118         {
119             return false
120         }
121         for i in 0..<self.arr.count
122         {
123             if self.arr[i] != that.arr[i]
124             {
125                 return false
126             }
127         }
128         return true
129     }
130     
131     func compareTo(_ that:Term) -> Int
132     {
133         if self.arr.count > that.arr.count {return -1}
134         if self.arr.count < that.arr.count {return 1}
135         for i in 0..<self.arr.count
136         {
137             var x:Int = 0
138             if self.arr[i] > that.arr[i]
139             {
140                 x = 1
141             }
142             else if self.arr[i] < that.arr[i]
143             {
144                 x = -1
145             }
146             else
147             {
148                 x = 0                
149             }
150             if x != 0 {return x}
151         }
152         return 0
153     }
154     
155     func times(_ that:Term) -> Term
156     {
157         var pro = Term(self.para * that.para)
158         for s in self.arr 
159         {
160             pro.arr.append(String(s))
161         }
162         for s in that.arr
163         {
164             pro.arr.append(String(s))
165         }
166         pro.arr = pro.arr.sorted(by:>)
167         return pro
168     }
169 }
170 
171 class Expression
172 {  
173     //Term List
174     var list:[Term] = [Term]()
175     var oper:Character = "+"   
176     
177     init(_ x:Int)
178     {
179         self.list.append(Term(x))
180     }
181     
182     init(_ s:String)
183     {
184         self.list.append(Term(s))
185     } 
186     
187     init(_ l:[Term])
188     {
189         self.list = l   
190     } 
191     
192     func times(_ that:Expression) -> Expression
193     {
194         var c:[Term] = [Term]()
195         for t1 in self.list
196         {
197             for t2 in that.list
198             {
199                 c.append(t1.times(t2))
200             }
201         }
202         c = combine(c)
203         return Expression(c)
204     }
205     
206     func plus(_ that:Expression,_ sgn:Int) -> Expression
207     {
208         var c:[Term] = [Term]()
209         for t in self.list
210         {
211             c.append(Term(t))
212         }
213         for t in that.list
214         {
215             var t2:Term = Term(t)
216             t2.para = t2.para * sgn
217             c.append(t2)                
218         }
219         c = combine(c)
220         return Expression(c)
221     }
222     
223     func cal(_ that:Expression) -> Expression
224     {
225         if oper == "+"
226         {               
227             return plus(that,1)
228         }
229         if oper == "-"
230         {
231             return plus(that,-1)
232         }
233         return times(that)
234     }
235     
236     func toList() -> [String]
237     {
238         var ans:[String] = [String]()
239         for t in list
240         {
241             var s:String = t.toString()
242             if s.count > 0 {ans.append(s)}
243         }
244         return ans
245     }
246     
247     func combine(_ a:[Term]) -> [Term]
248     {
249         var a = a
250         a.sort(by:{(t1:Term,t2:Term) -> Bool in
251                    return t1.compareTo(t2) < 0})
252         var c:[Term] = [Term]()
253         for t in a
254         {
255             if c.count != 0 && t.equals(c.last!)
256             {
257                 c[c.count - 1].para += t.para
258             }
259             else
260             {
261                 c.append(Term(t));
262             }
263         }
264         return c
265     }
266 }
267 
268 //String扩展
269 extension String {        
270     //subscript函数可以检索数组中的值
271     //直接按照索引方式截取指定索引的字符
272     subscript (_ i: Int) -> Character {
273         //读取字符
274         get {return self[index(startIndex, offsetBy: i)]}
275     }
276 }
277 
278 //Character扩展 
279 extension Character  
280 {  
281   //Character转ASCII整数值(定义小写为整数值)
282    var ascii: Int {
283        get {
284            return Int(self.unicodeScalars.first?.value ?? 0)
285        }       
286     }    
287     
288     func isDigit() -> Bool
289     {
290         if self.ascii > 47 && self.ascii < 58
291         {
292             return true            
293         }
294         return false
295     }
296     
297     func isLetter() -> Bool
298     {
299         if (self.ascii > 64 && self.ascii < 91) || self.ascii > 96 && self.ascii < 123
300         {
301             return true            
302         }
303         return false
304     }
305 }