An algorithm is a sequence of steps to solve a problem; there may be more than

one algorithm to solve a problem. The choice of a particular algorithm depends upon following consideration:-

1)      Time Complexity

2)      Space Complexity

Time Complexity:- The time complexity of an algorithm is the amount of time it needs to run to completion. Some of the reasons for studying time complexity are:-

       We may be interested to know in advance whether the program will provide a satisfactory real time response.

       There may be several possible solutions with different time requirement.

Space  Complexity:- The space complexity of an algorithm is the amount of memory it  needs to  run  to  completion. Some of  the  reasons to  study space complexity are: -

       There may be several possible solutions with in different space requirement.

       To estimate the size of the largest problem that a program can solve.