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# Python Program for Activity Selection Problem | Greedy Algo-1

• Difficulty Level : Medium
• Last Updated : 30 Dec, 2020

You are given n activities with their start and finish times. Select the maximum number of activities that can be performed by a single person, assuming that a person can only work on a single activity at a time.
Example:

```Example 1 : Consider the following 3 activities sorted
by finish time.
start[]  =  {10, 12, 20};
finish[] =  {20, 25, 30};
A person can perform at most two activities. The
maximum set of activities that can be executed
is {0, 2} [ These are indexes in start[] and
finish[] ]

Example 2 : Consider the following 6 activities
sorted by by finish time.
start[]  =  {1, 3, 0, 5, 8, 5};
finish[] =  {2, 4, 6, 7, 9, 9};
A person can perform at most four activities. The
maximum set of activities that can be executed
is {0, 1, 3, 4} [ These are indexes in start[] and
finish[] ]
```

## Python

 `"""The following implementation assumes that the activities``are already sorted according to their finish time"""`` ` `"""Prints a maximum set of activities that can be done by a``single person, one at a time"""``# n --> Total number of activities``# s[]--> An array that contains start time of all activities``# f[] --> An array that contains finish time of all activities`` ` `def` `printMaxActivities(s, f ):``    ``n ``=` `len``(f)``    ``print` `"The following activities are selected"`` ` `    ``# The first activity is always selected``    ``i ``=` `0``    ``print` `i,`` ` `    ``# Consider rest of the activities``    ``for` `j ``in` `xrange``(n):`` ` `        ``# If this activity has start time greater than``        ``# or equal to the finish time of previously``        ``# selected activity, then select it``        ``if` `s[j] >``=` `f[i]:``            ``print` `j,``            ``i ``=` `j`` ` `# Driver program to test above function``s ``=` `[``1``, ``3``, ``0``, ``5``, ``8``, ``5``]``f ``=` `[``2``, ``4``, ``6``, ``7``, ``9``, ``9``]``printMaxActivities(s, f)`` ` `# This code is contributed by Nikhil Kumar Singh`
Output:
```The following activities are selected
0 1 3 4
```

Please refer complete article on Activity Selection Problem | Greedy Algo-1 for more details!

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