20250214 finished.

src/problem/mod.rs

@@ -484,3 +484,5 @@ mod p1728_cat_and_mouse_ii;
 mod p1760_minimum_limit_of_balls_in_a_bag;
 
 mod p1742_maximum_number_of_balls_in_a_box;
+
+mod p1552_magnetic_force_between_two_balls;

src/problem/p1552_magnetic_force_between_two_balls.rs

@@ -0,0 +1,64 @@
+/**
+ * [1552] Magnetic Force Between Two Balls
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn max_distance(mut position: Vec<i32>, m: i32) -> i32 {
+        position.sort_unstable();
+
+        let mut left = i32::MAX;
+        for i in 0..position.len() - 1 {
+            left = left.min(position[i + 1] - position[i]);
+        }
+
+        let mut right = position[position.len() - 1] - position[0];
+
+        // [left, right]
+        let mut result = 0;
+        while left <= right {
+            let middle = (right - left) / 2 + left;
+
+            if Self::check(&position, m, middle) {
+                result = middle;
+                left = middle + 1;
+            } else {
+                right = middle - 1;
+            }
+        }
+
+        result
+    }
+
+    fn check(position: &Vec<i32>, m: i32, dis: i32) -> bool {
+        let mut pre = position[0];
+        let mut count = 1;
+
+        for i in 1..position.len() {
+            if position[i] - pre >= dis {
+                count += 1;
+                pre = position[i];
+            }
+        }
+
+        count >= m
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1552() {
+        assert_eq!(3, Solution::max_distance(vec![1, 2, 3, 4, 7], 3));
+        assert_eq!(
+            999_999_999,
+            Solution::max_distance(vec![5, 4, 3, 2, 1, 1_000_000_000], 2)
+        );
+    }
+}