Infix to postfix INPSTFIX

CodeChef-DSA-learners
,
1

Please help me in Infix to Postfix. I need some hints INPSTFIX

2

I suggest you to read all the rules regarding INFIX to POSTFIX conversion from Geek for Geeks or watch any video from youtube, then try implementing it.

3

I am getting run time error. Please help me

def op(nd):
    if(nd == '^'):
        return(3)
    elif(nd == '/' or nd == '*'):
        return(2)
    elif(nd == '+' or nd == '-'):
        return(1)


for i in range(int(input())):
    n = int(input())
    s = input()
    a = []
    b = []
    for i in s:
        if(i.isalpha()):
            b.append(i)
        #if(op(i) and len(a) == 0):
         #  a.append(i)
        elif(i == '('):
            a.append(i)
        elif(i == ')'):
            while(len(a) != 0 and a[-1] != '('):
                c = a.pop()
                b.append(c)
            a.pop()
        else:
            while(len(a) != 0 and a[-1] != '(' and (op(i) <= op(a[-1]))):
                c = a.pop()
                b.append(c)
            #else:
            a.append(i)
    while(len(a) != 0):
        c = a.pop()
        b.append(c)
    b = ''.join(map(str, b))
    #print(a)
    print(b)
4

guys and one more question: do we really need to use precedence in this ? from the examples it seems that every operation is closed under parenthesis, nothing about precedence is mentioned in the question.