{"id":2317,"date":"2016-10-27T21:17:49","date_gmt":"2016-10-27T13:17:49","guid":{"rendered":"http:\/\/boweihe.me\/?p=2317"},"modified":"2016-10-27T21:17:49","modified_gmt":"2016-10-27T13:17:49","slug":"leetcode-47-permutations-ii","status":"publish","type":"post","link":"https:\/\/dayandcarrot.space\/?p=2317","title":{"rendered":"LeetCode 47. Permutations II"},"content":{"rendered":"

\u7528\u56de\u6eaf\u6cd5\u5b8c\u6210\uff0c\u8ddf\u666e\u901a\u6392\u5217\u95ee\u9898\u4e0d\u540c\u7684\u662f\uff0c\u9700\u8981\u6392\u9664\u6389\u4e00\u4e9b\u91cd\u590d\u201c\u8def\u5f84\u201d\u3002
\n\u53ef\u4ee5\u8fd9\u6837\u505a\uff0c\u5148\u628a\u8f93\u5165\u6570\u7ec4\u6392\u4e2a\u5e8f\uff0c\u8fd9\u6837\u91cd\u590d\u7684\u6570\u5c31\u5728\u76f8\u90bb\u4f4d\u7f6e\u4e86\u3002\u968f\u540e\u5728\u56de\u6eaf\u63a2\u6c42\u7684\u8fc7\u7a0b\u4e2d\uff0c\u6211\u4eec\u8981\u4fdd\u8bc1\u76f8\u540c\u503c\u7684\u4e24\u4e2a\u6570nums[i], nums[j]\uff0c\u5982\u679ci<j\uff0c\u90a3\u904d\u5386\u53ea\u80fd\u6709\u4e00\u79cd\u6b21\u5e8f\uff1anums[i]\u5148\uff0cnums[j]\u540e\u3002
\n\u6362\u53e5\u8bdd\u8bf4\uff0c\u5c31\u662f\u5224\u65ad\u8fd9\u79cd\u60c5\u51b5\u662f\u9700\u8981\u63d0\u524d\u7ec8\u6b62\u7684\uff1a\u4e24\u4e2a\u6570nums[i]==nums[j] && i<j\uff0c\u4f46\u662fnums[i]\u8fd8\u6ca1\u6709\u88ab\u904d\u5386\u3002\u6240\u4ee5\u627e\u4e2a\u4e1c\u897f\u8bb0\u5f55\u4e00\u4e0b\u8bbf\u95ee\u5c31\u884c\u4e86\u3002
\n\u65f6\u95f4\u590d\u6742\u5ea6\u662fO(N!)\uff0c\u7a7a\u95f4\u590d\u6742\u5ea6\u662fO(N)<\/p>\n

class Solution {\npublic:\n    void permSub(vector<int>& nums, vector<int>& sub, vector<vector<int>>& results, vector<bool>& used){\n        if(sub.size() == nums.size()){\n            results.push_back(sub);\n            return;\n        } else {\n            for(int i=0; i<nums.size(); i++){\n                if(used[i])\n                    continue;\n                if(i>0 && nums[i]==nums[i-1] && !used[i-1])\n                    continue;\n                sub.push_back(nums[i]);\n                used[i] = true;\n                permSub(nums, sub, results, used);\n                sub.pop_back();\n                used[i] = false;\n            }\n        }\n    }\n    vector<vector<int>> permuteUnique(vector<int>& nums) {\n        sort(nums.begin(), nums.end());\n        vector<vector<int>> results;\n        vector<bool> used(nums.size(), false);\n        vector<int> sub;\n        permSub(nums, sub, results, used);\n        return results;\n    }\n};<\/pre>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
\u7528\u56de\u6eaf\u6cd5\u5b8c\u6210\uff0c\u8ddf\u666e\u901a\u6392\u5217\u95ee\u9898\u4e0d\u540c\u7684\u662f\uff0c\u9700\u8981\u6392\u9664\u6389\u4e00\u4e9b\u91cd\u590d\u201c\u8def\u5f84\u201d\u3002 \u53ef\u4ee5\u8fd9\u6837\u505a\uff0c\u5148\u628a\u8f93\u5165\u6570\u7ec4\u6392\u4e2a\u5e8f\uff0c\u8fd9\u6837\u91cd\u590d\u7684\u6570\u5c31\u5728\u76f8\u90bb\u4f4d\u7f6e\u4e86\u3002\u968f\u540e\u5728\u56de\u6eaf\u63a2\u6c42\u7684\u8fc7\u7a0b\u4e2d\uff0c\u6211\u4eec\u8981\u4fdd\u8bc1\u76f8\u540c\u503c\u7684\u4e24\u4e2a\u6570nums[i], nums[j]\uff0c\u5982\u679ci<j\uff0c\u90a3\u904d\u5386\u53ea\u80fd\u6709\u4e00\u79cd\u6b21\u5e8f\uff1anums[i]\u5148\uff0cnums[j]\u540e\u3002 \u6362\u53e5\u8bdd\u8bf4\uff0c\u5c31\u662f\u5224\u65ad\u8fd9\u79cd\u60c5\u51b5\u662f\u9700\u8981\u63d0\u524d\u7ec8\u6b62\u7684\uff1a\u4e24\u4e2a\u6570nums[i]==nums[j] && i<j\uff0c\u4f46\u662fnums[i]\u8fd8\u6ca1\u6709\u88ab\u904d\u5386\u3002\u6240\u4ee5\u627e\u4e2a\u4e1c\u897f\u8bb0\u5f55\u4e00\u4e0b\u8bbf\u95ee\u5c31\u884c\u4e86\u3002 \u65f6\u95f4\u590d\u6742\u5ea6\u662fO(N!)\uff0c\u7a7a\u95f4\u590d\u6742\u5ea6\u662fO(N) class Solution { public: void permSub(vector<int>& nums, vector<int>& sub, vector<vector<int>>& results, vector<bool>& used){ if(sub.size() == nums.size()){ results.push_back(sub); return; } else { for(int i=0; i<nums.size(); i++){ if(used[i]) continue; if(i>0 && nums[i]==nums[i-1] && !used[i-1]) continue; sub.push_back(nums[i]); used[i] = true; permSub(nums, sub, results, used); sub.pop_back(); used[i] = false; } } } […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[66],"class_list":["post-2317","post","type-post","status-publish","format-standard","hentry","category-study","tag-leetcode-oj"],"_links":{"self":[{"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/posts\/2317","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2317"}],"version-history":[{"count":0,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/posts\/2317\/revisions"}],"wp:attachment":[{"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2317"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2317"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2317"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}