feat: add solution in rust for k closest points

Author: bujosa

src/medium/k_closest_points_to_origin.rs

@@ -0,0 +1,48 @@
+#![allow(dead_code)]
+use std::collections::BinaryHeap;
+
+pub fn k_closest(points: Vec<Vec<i32>>, k: i32) -> Vec<Vec<i32>> {
+    let k = k as usize;
+    let mut pq = BinaryHeap::with_capacity(k);
+    for p in &points {
+        let d = p[0] * p[0] + p[1] * p[1];
+        pq.push((d, vec![p[0], p[1]]));
+        if pq.len() > k {
+            pq.pop();
+        }
+    }
+    pq.into_iter().map(|(_, p)| p).collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use std::vec;
+
+    use super::*;
+
+    fn compare_vec_of_vecs(a: Vec<Vec<i32>>, b: Vec<Vec<i32>>) -> bool {
+        let mut a = a;
+        let mut b = b;
+        a.sort();
+        b.sort();
+        a == b
+    }
+
+    #[test]
+    fn test_1() {
+        let points = vec![vec![1, 3], vec![-2, 2]];
+        let k = 1;
+        let expected = vec![vec![-2, 2]];
+        let result = k_closest(points, k);
+        assert!(compare_vec_of_vecs(result, expected));
+    }
+
+    #[test]
+    fn test_2() {
+        let points = vec![vec![3, 3], vec![5, -1], vec![-2, 4]];
+        let k = 2;
+        let expected = vec![vec![3, 3], vec![-2, 4]];
+        let result = k_closest(points, k);
+        assert!(compare_vec_of_vecs(result, expected));
+    }
+}