Pregunta de entrevista de Infogain

1. Sum of 2 numbers from unique elements list should be equal to target value and print there indexes too. 2. Count the frequency of elements in list and sort in descending order that dictionary on the basis of values. 3. Reverse the words of the sentence. 4. Analytic Question: How would you estimate the number of traffic signals that existed in your area prior to the year 2001?