Solved 0004

Author: guangsheng.li01

src/a0004_median_of_two_sorted_arrays.rs

@@ -0,0 +1,72 @@
+/*
+ * [0004] median-of-two-sorted-arrays
+ */
+
+pub struct Solution {}
+
+// solution impl starts here
+
+use std::cmp::{max, min};
+use std::i32::{MAX, MIN};
+impl Solution {
+    pub fn find_median_sorted_arrays(nums1: Vec<i32>, nums2: Vec<i32>) -> f64 {
+        let (m, n) = (nums1.len(), nums2.len());
+
+        if m > n {
+            return Solution::find_median_sorted_arrays(nums2, nums1);
+        }
+
+        let (mut low, mut high) = (0, 2 * m);
+        let (mut lmax1, mut lmax2, mut rmin1, mut rmin2) = (0, 0, 0, 0);
+        while low <= high {
+            let c1 = (low + high) / 2;
+            let c2 = m + n - c1;
+
+            lmax1 = if c1 == 0 { MIN } else { nums1[(c1 - 1) / 2] };
+            lmax2 = if c2 == 0 { MIN } else { nums2[(c2 - 1) / 2] };
+            rmin1 = if c1 == m * 2 { MAX } else { nums1[c1 / 2] };
+            rmin2 = if c2 == n * 2 { MAX } else { nums2[c2 / 2] };
+
+            if lmax1 > rmin2 {
+                high = c1 - 1;
+            } else if lmax2 > rmin1 {
+                low = c1 + 1;
+            } else {
+                break;
+            }
+        }
+        (max(lmax1, lmax2) + min(rmin1, rmin2)) as f64 / 2.0
+    }
+}
+
+// solution impl ends here
+
+// solution tests starts here
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_case0() {
+        assert_eq!(
+            Solution::find_median_sorted_arrays(vec![1, 3], vec![2]),
+            2f64
+        );
+    }
+
+    #[test]
+    fn test_case1() {
+        assert_eq!(
+            Solution::find_median_sorted_arrays(vec![1, 2], vec![3, 4]),
+            2.5f64
+        );
+    }
+
+    #[test]
+    fn test_case2() {
+        assert_eq!(Solution::find_median_sorted_arrays(vec![], vec![1]), 1f64);
+    }
+}
+
+// solution tests ends here

src/lib.rs

@@ -5,6 +5,7 @@ pub mod utils;
 
 mod a0000_sample;
 mod a0001_two_sum;
+mod a0004_median_of_two_sorted_arrays;
 mod a0007_reverse_integer;
 mod a0009_palindrome_number;
 mod a0026_remove_duplicates_from_sorted_array;