https://exercism.org/tracks/rust/exercises/difference-of-squares

rust/difference-of-squares/Cargo.toml

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+[package]
+edition = "2021"
+name = "difference-of-squares"
+version = "1.2.0"

rust/difference-of-squares/src/lib.rs

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+pub fn square_of_sum(n: u32) -> u32 {
+    /*
+    let mut sum = 0;
+    for i in 1..n + 1 {
+        sum += i;
+    }
+    sum.pow(2)
+    */
+    (1..n + 1).sum::<u32>().pow(2)
+}
+
+pub fn sum_of_squares(n: u32) -> u32 {
+    /*
+    let mut sum = 0;
+    for i in 1..n + 1 {
+        sum += i.pow(2);
+    }
+    sum
+    */
+    (1..n + 1).map(|x| x.pow(2)).sum::<u32>()
+}
+
+pub fn difference(n: u32) -> u32 {
+    square_of_sum(n) - sum_of_squares(n)
+}

rust/difference-of-squares/tests/difference-of-squares.rs

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+use difference_of_squares as squares;
+
+#[test]
+fn square_of_sum_1() {
+    assert_eq!(1, squares::square_of_sum(1));
+}
+
+#[test]
+fn square_of_sum_5() {
+    assert_eq!(225, squares::square_of_sum(5));
+}
+
+#[test]
+fn square_of_sum_100() {
+    assert_eq!(25_502_500, squares::square_of_sum(100));
+}
+
+#[test]
+fn sum_of_squares_1() {
+    assert_eq!(1, squares::sum_of_squares(1));
+}
+
+#[test]
+fn sum_of_squares_5() {
+    assert_eq!(55, squares::sum_of_squares(5));
+}
+
+#[test]
+fn sum_of_squares_100() {
+    assert_eq!(338_350, squares::sum_of_squares(100));
+}
+
+#[test]
+fn difference_1() {
+    assert_eq!(0, squares::difference(1));
+}
+
+#[test]
+fn difference_5() {
+    assert_eq!(170, squares::difference(5));
+}
+
+#[test]
+fn difference_100() {
+    assert_eq!(25_164_150, squares::difference(100));
+}