Given an infix expression in the form of string str. Convert this infix expression to postfix expression.
Infix expression: The expression of the form a op b. When an operator is in-between every pair of operands.
Postfix expression: The expression of the form a b op. When an operator is followed for every pair of operands.
Note: The order of precedence is: ^ greater than * equals to / greater than + equals to -.
Example 1:
Input: str = "a+b(c^d-e)^(f+gh)-i"
Output: abcd^e-fgh+^+i-
Explanation:
After converting the infix expression
into postfix expression, the resultant
expression will be abcd^e-fgh+^+i-
Example 2:
Input: str = "A(B+C)/D"
Output: ABC+D/
Explanation:
After converting the infix expression
into postfix expression, the resultant
expression will be ABC+*D/

Your Task:
This is a function problem. You only need to complete the function infixToPostfix() that takes a string(Infix Expression) as a parameter and returns a string(postfix expression). The printing is done automatically by the driver code.
Expected Time Complexity: O(|str|).
Expected Auxiliary Space: O(|str|).
Constraints:
1 ≤ |str| ≤ 10^{5}

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