{"id":1540,"date":"2022-01-08T18:02:01","date_gmt":"2022-01-08T10:02:01","guid":{"rendered":"http:\/\/139.9.1.231\/?p=1540"},"modified":"2022-01-08T21:58:45","modified_gmt":"2022-01-08T13:58:45","slug":"leetcodeday4","status":"publish","type":"post","link":"http:\/\/139.9.1.231\/index.php\/2022\/01\/08\/leetcodeday4\/","title":{"rendered":"leetcodeday4\u5bfb\u627e\u4e24\u4e2a\u6b63\u5e8f\u6570\u7ec4\u7684\u4e2d\u4f4d\u6570"},"content":{"rendered":"\n

\u7ed9\u5b9a\u4e24\u4e2a\u5927\u5c0f\u5206\u522b\u4e3a m \u548c n \u7684\u6b63\u5e8f\uff08\u4ece\u5c0f\u5230\u5927\uff09\u6570\u7ec4 nums1 \u548c nums2\u3002\u8bf7\u4f60\u627e\u51fa\u5e76\u8fd4\u56de\u8fd9\u4e24\u4e2a\u6b63\u5e8f\u6570\u7ec4\u7684 \u4e2d\u4f4d\u6570 \u3002<\/p>\n\n\n\n

\u7b97\u6cd5\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u5e94\u8be5\u4e3a O(log (m+n)) \u3002<\/p>\n\n\n\n

\u793a\u4f8b 1\uff1a<\/p>\n\n\n\n

\u8f93\u5165\uff1anums1 = [1,3], nums2 = [2]
\u8f93\u51fa\uff1a2.00000
\u89e3\u91ca\uff1a\u5408\u5e76\u6570\u7ec4 = [1,2,3] \uff0c\u4e2d\u4f4d\u6570 2
\u793a\u4f8b 2\uff1a<\/p>\n\n\n\n

\u8f93\u5165\uff1anums1 = [1,2], nums2 = [3,4]
\u8f93\u51fa\uff1a2.50000
\u89e3\u91ca\uff1a\u5408\u5e76\u6570\u7ec4 = [1,2,3,4] \uff0c\u4e2d\u4f4d\u6570 (2 + 3) \/ 2 = 2.5
\u793a\u4f8b 3\uff1a<\/p>\n\n\n\n

\u8f93\u5165\uff1anums1 = [0,0], nums2 = [0,0]
\u8f93\u51fa\uff1a0.00000
\u793a\u4f8b 4\uff1a<\/p>\n\n\n\n

\u8f93\u5165\uff1anums1 = [], nums2 = [1]
\u8f93\u51fa\uff1a1.00000<\/p>\n\n\n\n

\u7b2c\u4e00\u6b21\u89e3\u9898\uff1a<\/p>\n\n\n\n

# @lc code=start\nclass Solution:\n    def findMedianSortedArrays(self, nums1: List[int], nums2: List[int]) -> float:\n        nums3=sorted(nums1+nums2)\n        length= len(nums3)\n        return nums3[length\/\/2] if length%2==1 else (nums3[length\/\/2]+nums3[length\/\/2-1])\/2\n\n# @lc code=end<\/code><\/pre>\n\n\n\n
\"\"<\/figure><\/div>\n\n\n\n
\u5360\u7528\u7684\u5185\u5b58\u592a\u9ad8\u4e86….<\/p>\n\n\n\n
\u6539\u8fdb\uff1a<\/p>\n\n\n\n
\u4e0d\u9700\u8981\u5408\u5e76\u4e24\u4e2a\u6709\u5e8f\u6570\u7ec4\uff0c\u53ea\u8981\u627e\u5230\u4e2d\u4f4d\u6570\u7684\u4f4d\u7f6e\u5373\u53ef\u3002\u7531\u4e8e\u4e24\u4e2a\u6570\u7ec4\u7684\u957f\u5ea6\u5df2\u77e5\uff0c\u56e0\u6b64\u4e2d\u4f4d\u6570\u5bf9\u5e94\u7684\u4e24\u4e2a\u6570\u7ec4\u7684\u4e0b\u6807\u4e4b\u548c\u4e5f\u662f\u5df2\u77e5\u7684\u3002\u7ef4\u62a4\u4e24\u4e2a\u6307\u9488\uff0c\u521d\u59cb\u65f6\u5206\u522b\u6307\u5411\u4e24\u4e2a\u6570\u7ec4\u7684\u4e0b\u6807 0 \u7684\u4f4d\u7f6e\uff0c\u6bcf\u6b21\u5c06\u6307\u5411\u8f83\u5c0f\u503c\u7684\u6307\u9488\u540e\u79fb\u4e00\u4f4d\uff08\u5982\u679c\u4e00\u4e2a\u6307\u9488\u5df2\u7ecf\u5230\u8fbe\u6570\u7ec4\u672b\u5c3e\uff0c\u5219\u53ea\u9700\u8981\u79fb\u52a8\u53e6\u4e00\u4e2a\u6570\u7ec4\u7684\u6307\u9488\uff09\uff0c\u76f4\u5230\u5230\u8fbe\u4e2d\u4f4d\u6570\u7684\u4f4d\u7f6e\u3002<\/p>\n\n\n\n
class Solution:
def findMedianSortedArrays(self, nums1: List[int], nums2: List[int]) -> float:
def getKthElement(k):
“””
– \u4e3b\u8981\u601d\u8def\uff1a\u8981\u627e\u5230\u7b2c k (k>1) \u5c0f\u7684\u5143\u7d20\uff0c\u90a3\u4e48\u5c31\u53d6 pivot1 = nums1[k\/2-1] \u548c pivot2 = nums2[k\/2-1] \u8fdb\u884c\u6bd4\u8f83
– \u8fd9\u91cc\u7684 “\/” \u8868\u793a\u6574\u9664
– nums1 \u4e2d\u5c0f\u4e8e\u7b49\u4e8e pivot1 \u7684\u5143\u7d20\u6709 nums1[0 .. k\/2-2] \u5171\u8ba1 k\/2-1 \u4e2a
– nums2 \u4e2d\u5c0f\u4e8e\u7b49\u4e8e pivot2 \u7684\u5143\u7d20\u6709 nums2[0 .. k\/2-2] \u5171\u8ba1 k\/2-1 \u4e2a
– \u53d6 pivot = min(pivot1, pivot2)\uff0c\u4e24\u4e2a\u6570\u7ec4\u4e2d\u5c0f\u4e8e\u7b49\u4e8e pivot \u7684\u5143\u7d20\u5171\u8ba1\u4e0d\u4f1a\u8d85\u8fc7 (k\/2-1) + (k\/2-1) <= k-2 \u4e2a
– \u8fd9\u6837 pivot \u672c\u8eab\u6700\u5927\u4e5f\u53ea\u80fd\u662f\u7b2c k-1 \u5c0f\u7684\u5143\u7d20
– \u5982\u679c pivot = pivot1\uff0c\u90a3\u4e48 nums1[0 .. k\/2-1] \u90fd\u4e0d\u53ef\u80fd\u662f\u7b2c k \u5c0f\u7684\u5143\u7d20\u3002\u628a\u8fd9\u4e9b\u5143\u7d20\u5168\u90e8 “\u5220\u9664”\uff0c\u5269\u4e0b\u7684\u4f5c\u4e3a\u65b0\u7684 nums1 \u6570\u7ec4
– \u5982\u679c pivot = pivot2\uff0c\u90a3\u4e48 nums2[0 .. k\/2-1] \u90fd\u4e0d\u53ef\u80fd\u662f\u7b2c k \u5c0f\u7684\u5143\u7d20\u3002\u628a\u8fd9\u4e9b\u5143\u7d20\u5168\u90e8 “\u5220\u9664”\uff0c\u5269\u4e0b\u7684\u4f5c\u4e3a\u65b0\u7684 nums2 \u6570\u7ec4
– \u7531\u4e8e\u6211\u4eec “\u5220\u9664” \u4e86\u4e00\u4e9b\u5143\u7d20\uff08\u8fd9\u4e9b\u5143\u7d20\u90fd\u6bd4\u7b2c k \u5c0f\u7684\u5143\u7d20\u8981\u5c0f\uff09\uff0c\u56e0\u6b64\u9700\u8981\u4fee\u6539 k \u7684\u503c\uff0c\u51cf\u53bb\u5220\u9664\u7684\u6570\u7684\u4e2a\u6570
“””<\/p>\n\n\n\n
        index1, index2 = 0, 0\n        while True:\n            # \u7279\u6b8a\u60c5\u51b5\n            if index1 == m:\n                return nums2[index2 + k - 1]\n            if index2 == n:\n                return nums1[index1 + k - 1]\n            if k == 1:\n                return min(nums1[index1], nums2[index2])\n\n            # \u6b63\u5e38\u60c5\u51b5\n            newIndex1 = min(index1 + k \/\/ 2 - 1, m - 1)\n            newIndex2 = min(index2 + k \/\/ 2 - 1, n - 1)\n            pivot1, pivot2 = nums1[newIndex1], nums2[newIndex2]\n            if pivot1 <= pivot2:\n                k -= newIndex1 - index1 + 1\n                index1 = newIndex1 + 1\n            else:\n                k -= newIndex2 - index2 + 1\n                index2 = newIndex2 + 1\n\n    m, n = len(nums1), len(nums2)\n    totalLength = m + n\n    if totalLength % 2 == 1:\n        return getKthElement((totalLength + 1) \/\/ 2)\n    else:\n        return (getKthElement(totalLength \/\/ 2) + getKthElement(totalLength \/\/ 2 + 1)) \/ 2<\/code><\/pre>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
\u7ed9\u5b9a\u4e24\u4e2a\u5927\u5c0f\u5206\u522b\u4e3a m \u548c n \u7684\u6b63\u5e8f\uff08\u4ece\u5c0f\u5230\u5927\uff09\u6570\u7ec4 nums1 \u548c nums2\u3002\u8bf7\u4f60\u627e … \u7ee7\u7eed\u9605\u8bfbleetcodeday4\u5bfb\u627e\u4e24\u4e2a\u6b63\u5e8f\u6570\u7ec4\u7684\u4e2d\u4f4d\u6570<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6],"tags":[],"_links":{"self":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/1540"}],"collection":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/comments?post=1540"}],"version-history":[{"count":6,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/1540\/revisions"}],"predecessor-version":[{"id":1662,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/1540\/revisions\/1662"}],"wp:attachment":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/media?parent=1540"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/categories?post=1540"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/tags?post=1540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}