Coding For You

Given a 2D screen, location of a pixel in the screen and a color, replace color of the given pixel and all adjacent same colored pixels with the given color.

Aho–Corasick algorithm is a string-searching algorithm invented by Alfred V. Aho and Margaret J. Corasick. It is a kind of dictionary-matching algorithm that locates elements of a finite set of strings within an input text. It matches all strings simultaneously.

According to Euler’s four square identity, the product of any two numbers a and b can be expressed as a sum of four squares if a and b both can individually be expressed as sum of four squares.