﻿ Python: Find a pair of elements from a given array whose sum equals a specific target number - w3resource

# Python: Find a pair of elements from a given array whose sum equals a specific target number

## Python Class: Exercise-5 with Solution

Write a Python class to find a pair of elements (indices of the two numbers) from a given array whose sum equals a specific target number.

Sample Solution-1:

Python Code:

``````class py_solution:
def twoSum(self, nums, target):
lookup = {}
for i, num in enumerate(nums):
if target - num in lookup:
return (lookup[target - num], i )
lookup[num] = i
print("index1=%d, index2=%d" % py_solution().twoSum((10,20,10,40,50,60,70),50))
```
```

Sample Output:

```index1=2, index2=3
```

Pictorial Presentation: Flowchart: ## Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:

Sample Solution-2:

Python Code:

``````class py_solution(object):
def twoSum(self, nums, target_num):
"""
:type nums: list[int]
:type target: int
:return type: list[int]
"""
result_dict = dict()
pos = 0
while pos < len(nums):
if (target_num - nums[pos]) not in result_dict:
result_dict[nums[pos]] = pos
pos += 1
else:
return [result_dict[target_num - nums[pos]], pos]
print(py_solution().twoSum([10,20,10,40,50,60,70],50))
print(py_solution().twoSum([10,20,10,40,50,60,70],52))
```
```

Sample Output:

```[2, 3]
None
```

Flowchart: ## Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:

Python Code Editor:

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## Python: Tips of the Day

Get Current Process Id:

```import os
os.getpid()
```
`21423`

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