JohnDow questions

• Fastest way to check if value is in array many times
• String to Dictionary Python
• Fastest way to find sum of any rectangle in matrix
• Java string to math equation [duplicate]
• Split matrix into 4 sub-matrices with lowest difference between their sum
• TypeError: unsupported operand type(s) for +: 'dict_items' and 'dict_items'

JohnDow answers