problems(rs): add “1232. Check If It Is a Straight Line”

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/rs/check-if-it-is-a-straight-line.rs

@@ -0,0 +1,58 @@
+struct Solution {}
+impl Solution {
+    fn x_diff(a: &[i32], b: &[i32]) -> i32 {
+        a[0] - b[0]
+    }
+
+    fn y_diff(a: &[i32], b: &[i32]) -> i32 {
+        a[1] - b[1]
+    }
+
+    pub fn check_straight_line(coordinates: Vec<Vec<i32>>) -> bool {
+        assert!(coordinates.len() > 1);
+
+        let (dx, dy) = (
+            Solution::x_diff(&coordinates[0], &coordinates[1]),
+            Solution::y_diff(&coordinates[0], &coordinates[1]),
+        );
+
+        coordinates.iter().all(|pt| {
+            dx * Solution::y_diff(pt, &coordinates[0]) == dy * Solution::x_diff(pt, &coordinates[0])
+        })
+    }
+}
+
+fn main() {}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // Input: coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]
+    // Output: true
+    #[test]
+    fn example_1() {
+        assert!(Solution::check_straight_line(vec![
+            vec![1, 2],
+            vec![2, 3],
+            vec![3, 4],
+            vec![4, 5],
+            vec![5, 6],
+            vec![6, 7]
+        ]));
+    }
+
+    // Input: coordinates = [[1,1],[2,2],[3,4],[4,5],[5,6],[7,7]]
+    // Output: false
+    #[test]
+    fn example_2() {
+        assert!(!Solution::check_straight_line(vec![
+            vec![1, 1],
+            vec![2, 2],
+            vec![3, 4],
+            vec![4, 5],
+            vec![5, 6],
+            vec![7, 7]
+        ]));
+    }
+}