leetcode 4

4. Median of Two Sorted Arrays/code1.py

@@ -5,18 +5,44 @@
 class Solution:
 
     def findMedianSortedArrays(self, nums1: List[int], nums2: List[int]) -> float:
+        n, m = len(nums1), len(nums2)
+        left = (n + m + 1) // 2
+        right = (n + m + 2) // 2
 
-        return
+        return (get_median(nums1, 0, n-1, nums2, 0, m-1, left) +
+                get_median(nums1, 0, n-1, nums2, 0, m-1, right)) / 2
+
+
+def get_median(arr1, start1, end1, arr2, start2, end2, k):
+    len1 = end1 - start1 + 1
+    len2 = end2 - start2 + 1
+
+    if len1 > len2:
+        return get_median(arr2, start2, end2, arr1, start1, end1, k)
+    if len1 == 0:
+        return arr2[start2+k-1]
+
+    if k == 1:
+        return min(arr1[start1], arr2[start2])
+
+    i = start1 + min(len1, k // 2) - 1
+    j = start2 + min(len2, k // 2) - 1
+
+    if arr1[i] > arr2[j]:
+        return get_median(arr1, start1, end1, arr2, j+1, end2, k-(j-start2+1))
+    else:
+        return get_median(arr1, i+1, end1, arr2, start2, end2, k-(i-start1+1))
 
 
 if __name__ == '__main__':
     solution = Solution()
-    nums1 = [1, 2, 7, 9]
-    nums2 = [3, 4]
+    # nums1 = [1, 2, 7, 9]
+    # nums2 = [3, 4]
     # nums1 = [1, 3]
     # nums2 = [2]
     # nums1 = []
     # nums2 = [1]
+    nums1 = [4, 5, 6, 7]
+    nums2 = [1, 2, 3]
 
-    print((solution.findMedianSortedArrays(nums1, nums2)))
-
+    print(solution.findMedianSortedArrays(nums1, nums2))