Create 0004-median-of-two-sorted-arrays.swift

Author: drxlx

swift/0004-median-of-two-sorted-arrays.swift

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+class Solution {
+    func findMedianSortedArrays(_ nums1: [Int], _ nums2: [Int]) -> Double {
+        if nums1.count > nums2.count {
+            return findMedianSortedArrays(nums2, nums1)
+        }
+
+        var m = nums1.count
+        var n = nums2.count
+        var l = 0
+        var r = m
+
+        while l <= r {
+            var pa = (l + r) / 2
+            var pb = (m + n + 1) / 2 - pa
+
+            var maxLeftA = pa == 0 ? Int.min : nums1[pa - 1]
+            var minRightA = pa == m ? Int.max : nums1[pa]
+            var maxLeftB = pb == 0 ? Int.min : nums2[pb - 1]
+            var minRightB = pb == n ? Int.max : nums2[pb]
+
+            if maxLeftA <= minRightB && maxLeftB <= minRightA {
+                if (m + n) % 2 == 0 {
+                    return Double((max(maxLeftA, maxLeftB) + min(minRightA, minRightB))) / 2.0
+                } else {
+                    return Double(max(maxLeftA, maxLeftB))
+                }
+            } else if maxLeftA > minRightB {
+                r = pa - 1
+            } else {
+                l = pa + 1
+            }
+        }
+
+        return 0.0
+    }
+}