{ "data": { "question": { "questionId": "781", "questionFrontendId": "770", "categoryTitle": "Algorithms", "boundTopicId": 1940, "title": "Basic Calculator IV", "titleSlug": "basic-calculator-iv", "content": "
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"]
"2x"
or "-x"
.Expressions are evaluated in the usual order: brackets first, then multiplication, then addition and subtraction.
\n\nexpression = "1 + 2 * 3"
has an answer of ["7"]
.The format of the output is as follows:
\n\n"b*a*c"
, only "a*b*c"
."a*a*b*c"
has degree 4
.["-2*a*a*a", "3*a*a*b", "3*b*b", "4*a", "5*c", "-6"]
.0
are not included.\n\t"0"
has an output of []
.\n
Example 1:
\n\n\nInput: expression = "e + 8 - a + 5", evalvars = ["e"], evalints = [1]\nOutput: ["-1*a","14"]\n\n\n
Example 2:
\n\n\nInput: expression = "e - 8 + temperature - pressure", evalvars = ["e", "temperature"], evalints = [1, 12]\nOutput: ["-1*pressure","5"]\n\n\n
Example 3:
\n\n\nInput: expression = "(e + 8) * (e - 8)", evalvars = [], evalints = []\nOutput: ["1*e*e","-64"]\n\n\n
\n
Constraints:
\n\n1 <= expression.length <= 250
expression
consists of lowercase English letters, digits, '+'
, '-'
, '*'
, '('
, ')'
, ' '
.expression
does not contain any leading or trailing spaces.expression
are separated by a single space.0 <= evalvars.length <= 100
1 <= evalvars[i].length <= 20
evalvars[i]
consists of lowercase English letters.evalints.length == evalvars.length
-100 <= evalints[i] <= 100
给定一个表达式如 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\"]
\"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。
\n\nexpression = \"1 + 2 * 3\"
的答案是 [\"7\"]
。输出格式如下:
\n\n“b*a*c”
这样的项,只写 “a*b*c”
。\"a*a*b*c\"
的次数为 4。[\"-2*a*a*a\", \"3*a*a*b\", \"3*b*b\", \"4*a\", \"5*c\", \"-6\"]
。0
的项(包括常数项)不包括在内。\n\t“0”
的表达式输出为 []
。\n\n
示例 1:
\n\n\n输入:expression = \"e + 8 - a + 5\", evalvars = [\"e\"], evalints = [1]\n输出:[\"-1*a\",\"14\"]\n\n\n
示例 2:
\n\n\n输入:expression = \"e - 8 + temperature - pressure\",\nevalvars = [\"e\", \"temperature\"], evalints = [1, 12]\n输出:[\"-1*pressure\",\"5\"]\n\n\n
示例 3:
\n\n\n输入:expression = \"(e + 8) * (e - 8)\", evalvars = [], evalints = []\n输出:[\"1*e*e\",\"-64\"]\n\n\n
\n\n
提示:
\n\n1 <= expression.length <= 250
expression
由小写英文字母,数字 '+'
, '-'
, '*'
, '('
, ')'
, ' '
组成expression
不包含任何前空格或后空格expression
中的所有符号都用一个空格隔开0 <= evalvars.length <= 100
1 <= evalvars[i].length <= 20
evalvars[i]
由小写英文字母组成evalints.length == evalvars.length
-100 <= evalints[i] <= 100
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