leetcode中如何为运算表达式设计优先级

示例 1:

输入: "2-1-1"输出: [0, 2]解释: ((2-1)-1) = 0 (2-(1-1)) = 2示例 2:

输入: "2*3-4*5"输出: [-34, -14, -10, -10, 10]解释: (2*(3-(4*5))) = -34 ((2*3)-(4*5)) = -14 ((2*(3-4))*5) = -10 (2*((3-4)*5)) = -10 (((2*3)-4)*5) = 10

func diffWaysToCompute(input string) []int {    t:=strToTok(input)    fmt.Println(t)    return cal(t)}
func cal(t[]Token)[]int{    var r []int    if len(t)==1{        r=append(r,t[0].value)        return r    }    for i:=1;i      la:=cal(t[:i])      ra:=cal(t[i+1:])      for _,l:=range la{          for _,r1:=range ra{                switch t[i].op{                    case '+':                        r=append(r,l+r1)                    case '-':                        r=append(r,l-r1)                    case '*':                        r=append(r,l*r1)                }          }      }    }    return r}
type Token struct{    tokenType int  //0 num 1 op    value int    op byte}
func strToTok(input string)[]Token{    var r []Token    for i:=0;i        if input[i]=='+' || input[i]=='-' || input[i]=='*' {            r=append(r,Token{                tokenType:1,                op:input[i],            })            i++        }        num:=0        for i='0' && input[i]<='9'{            num=num*10+int(input[i]-'0')            i++        }        r=append(r,Token{            value:num,        })    }    return r}