题解 | #四则运算#单栈解法
四则运算
https://www.nowcoder.com/practice/9999764a61484d819056f807d2a91f1e
package main
import (
"fmt"
// "sort"
"strings"
"bufio"
"os"
// "strconv"
)
func main(){
input := bufio.NewScanner(os.Stdin)
input.Scan()
data := input.Text()
a := strings.Replace(data, "{", "(", -1)
b := strings.Replace(a, "}", ")", -1)
c := strings.Replace(b, "[", "(", -1)
d := strings.Replace(c, "]", ")", -1)
// fmt.Println(d)
fmt.Println(cal(d))
}
func cal(s string)int{
// fmt.Println(s, len(s))
num := 0
res := 0
sign := byte('+')
if s[0]=='-'{
sign=byte('-')
}
stack := []int{}
for i := 0;i<len(s);i++{
if isDigit(s[i]){
num = num*10 + int(s[i]-'0')
}
if s[i]=='(' {
count := 1
j := i+1
for count>0{
if s[j]=='('{
count++
}else if s[j]==')'{
count--
}
j++
}
num = cal(s[i+1:j-1])
i = j-1
}
if !isDigit(s[i]) || i == len(s)-1{
if sign == '+'{
stack = append(stack, num)
}else if sign == '-'{
stack = append(stack, -num)
}else if sign == '*'{
stack[len(stack)-1] *= num
}else if sign == '/'{
stack[len(stack)-1] /= num
}
sign = s[i]
num = 0
}
if s[i]==')'{
continue
}
}
for _,i := range stack{
res += i
}
return res
}
func isDigit(n byte)bool{
if n>='0'&&n<='9'{
return true
}else{
return false
}
}
