{"id":5340,"date":"2019-07-22T22:24:40","date_gmt":"2019-07-23T05:24:40","guid":{"rendered":"https:\/\/zxi.mytechroad.com\/blog\/?p=5340"},"modified":"2019-07-22T22:25:45","modified_gmt":"2019-07-23T05:25:45","slug":"leetcode-217-contains-duplicate","status":"publish","type":"post","link":"https:\/\/zxi.mytechroad.com\/blog\/hashtable\/leetcode-217-contains-duplicate\/","title":{"rendered":"\u82b1\u82b1\u9171 LeetCode 217. Contains Duplicate"},"content":{"rendered":"\n

Given an array of integers, find if the array contains any duplicates.<\/p>\n\n\n\n

Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.<\/p>\n\n\n\n

Example 1:<\/strong><\/p>\n\n\n\n

Input:<\/strong> [1,2,3,1]\nOutput:<\/strong> true<\/pre>\n\n\n\n
Example 2:<\/strong><\/p>\n\n\n\n
Input: <\/strong>[1,2,3,4]\nOutput:<\/strong> false<\/pre>\n\n\n\n
Example 3:<\/strong><\/p>\n\n\n\n
Input: <\/strong>[1,1,1,3,3,4,3,2,4,2]\nOutput:<\/strong> true<\/pre>\n\n\n\n
Solution 1: HashTable<\/strong><\/h2>\n\n\n\n
Time complexity: O(n)
Space complexity: O(n)<\/p>\n\n\n\n
\n
C++<\/h2>\n
\n\n
\n\/\/ Author: Huahua, 48ms\/16.5MB\nclass Solution {\npublic:\n  bool containsDuplicate(vector& nums) {\n    unordered_set s;\n    for (int num : nums)\n      if (!s.insert(num).second) return true;\n    return false;\n  }\n};\n<\/pre>\n<\/div><\/div>\n\n\n\n
Solution 2: Sorting<\/strong><\/h2>\n\n\n\n
Time complexity: O(nlogn)
Space complexity: O(1)<\/p>\n\n\n\n
\n
C++<\/h2>\n
\n\n
\n\/\/ Author: Huahua, 28ms\/11.4MB\nclass Solution {\npublic:\n  bool containsDuplicate(vector& nums) {\n    sort(begin(nums), end(nums));\n    for (int i = 1; i < nums.size(); ++i)\n      if (nums[i] == nums[i - 1]) return true;\n    return false;\n  }\n};\n<\/pre>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"
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