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QuestionGiven an arraySofnintegers, are there elementsa,b,c, anddinSsuch thata+b+c+d= target? Find all unique quadruplets in the array which gives the... 阅读全文
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QuestionGiven a linked list, reverse the nodes of a linked listkat a time and return its modified list.If the number of nodes is not a multiple ofkthe... 阅读全文
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QuestionGiven a linked list, swap every two adjacent nodes and return its head.For example,Given1->2->3->4, you should return the list as2->1->4->3.Yo... 阅读全文
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QuestionGiven a binary tree containing digits from0-9only, each root-to-leaf path could represent a number.An example is the root-to-leaf path1->2->3w... 阅读全文
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Sum类的题目一般这样：input: nums[], targetoutput: satisfied arrays/ lists/ number拿到题目，首先分析：1. 是几个数的sum2. sum是要求等于target还是小于还是大于还是closest3. 返回的是原数组下标还是其他对于这类题目，... 阅读全文