Which of the following permutations can be obtained in the output(in the same order),using a stack assuming that the input is the sequence 1,2,3,4,5 in that order?
If the sequence of operations- push (1), push (2), pop, push (1), push (2), pop, pop, pop, push (2), pop, are performed on a stack, the sequenceof popped out values are
In evaluating the arithmetic expression 2 * 3-(4+5), using stacks to evaluate its equivalent post-fix form, which of the following stack configuration is not possible?
The postfix equivalent is 2 3 * 4 5 + -. For evaluating this using stack, starting from the left, we have to scan one by one. If it is an operand push. if it is an operator, pop it twice, apply the operator on the popped out entries and push the result onto the stack. If we follow this, we can find configuration in option (d) is not possible.