20: Add solution for Rust track exercise "Difference Of Squares".

Dependencies

• [2] QK6XE5XF 13: Add Rust track exercises "Beer Song", "Proverb", "Difference Of Squares", "Sum Of Multiples", "Grains", "Prime Factors", "Armstrong Numbers" and "Reverse String".

Change contents

• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 5
  [2.30254]→[2.30254:30300](∅→∅)
  − assert_eq!(1, squares::square_of_sum(1));
  [2.30254]

  [2.30300]
  + assert_eq!(1, squares::square_of_sum(1));
• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 11
  [2.30349]→[2.30349:30397](∅→∅)
  − assert_eq!(225, squares::square_of_sum(5));
  [2.30349]

  [2.30397]
  + assert_eq!(225, squares::square_of_sum(5));
• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 17
  [2.30448]→[2.30448:30505](∅→∅)
  − assert_eq!(25_502_500, squares::square_of_sum(100));
  [2.30448]

  [2.30505]
  + assert_eq!(25_502_500, squares::square_of_sum(100));
• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 23
  [2.30555]→[2.30555:30602](∅→∅)
  − assert_eq!(1, squares::sum_of_squares(1));
  [2.30555]

  [2.30602]
  + assert_eq!(1, squares::sum_of_squares(1));
• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 29
  [2.30652]→[2.30652:30700](∅→∅)
  − assert_eq!(55, squares::sum_of_squares(5));
  [2.30652]

  [2.30700]
  + assert_eq!(55, squares::sum_of_squares(5));
• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 35
  [2.30752]→[2.30752:30807](∅→∅)
  − assert_eq!(338_350, squares::sum_of_squares(100));
  [2.30752]

  [2.30807]
  + assert_eq!(338_350, squares::sum_of_squares(100));
• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 41
  [2.30853]→[2.30853:30896](∅→∅)
  − assert_eq!(0, squares::difference(1));
  [2.30853]

  [2.30896]
  + assert_eq!(0, squares::difference(1));
• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 47
  [2.30942]→[2.30942:30987](∅→∅)
  − assert_eq!(170, squares::difference(5));
  [2.30942]

  [2.30987]
  + assert_eq!(170, squares::difference(5));
• replacement in rust/difference-of-squares/tests/difference-of-squares.rs at line 53
  [2.31035]→[2.31035:31089](∅→∅)
  − assert_eq!(25_164_150, squares::difference(100));
  [2.31035]

  [2.31089]
  + assert_eq!(25_164_150, squares::difference(100));
• edit in rust/difference-of-squares/src/lib.rs at line 1
  [2.31139]

  [2.31140]
  + // https://en.wikipedia.org/wiki/Triangular_number
• replacement in rust/difference-of-squares/src/lib.rs at line 3
  [2.31178]→[2.31178:31227](∅→∅)
  − unimplemented!("square of sum of 1...{}", n)
  [2.31178]

  [2.31227]
  + (n * (n + 1) / 2).pow(2)
• edit in rust/difference-of-squares/src/lib.rs at line 6
  [2.31230]

  [2.31230]
  + // https://en.wikipedia.org/wiki/Square_pyramidal_number
• replacement in rust/difference-of-squares/src/lib.rs at line 8
  [2.31269]→[2.31269:31319](∅→∅)
  − unimplemented!("sum of squares of 1...{}", n)
  [2.31269]

  [2.31319]
  + n * (n + 1) * (2 * n + 1) / 6
• replacement in rust/difference-of-squares/src/lib.rs at line 12
  [2.31357]→[2.31357:31483](∅→∅)
  − unimplemented!(

  − "difference between square of sum of 1...{n} and sum of squares of 1...{n}",

  − n = n,

  − )
  [2.31357]

  [2.31483]
  + square_of_sum(n) - sum_of_squares(n)