最近遇到對聊天有困擾的朋友,所以我買了這本書,並分享筆記給他,如果對他有幫助,也能幫到一樣有困擾的小夥伴們就太好了。
204. Count Primes
Count the number of prime numbers less than a non-negative number, n.
Example 1:
1 | Input: n = 10 |
Example 2:
1 | Input: n = 0 |
Example 3:
1 | Input: n = 1 |
88. Merge Sorted Array
Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.
The number of elements initialized in nums1 and nums2 are m and n respectively. You may assume that nums1 has enough space (size that is equal to m + n) to hold additional elements from nums2.
Example 1:
1 | Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3 |
Example 2:
1 | Input: nums1 = [1], m = 1, nums2 = [], n = 0 |
28. Implement strStr()
Implement strStr().
Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Clarification:
What should we return when needle is an empty string? This is a great question to ask during an interview.
For the purpose of this problem, we will return 0 when needle is an empty string. This is consistent to C’s strstr() and Java’s indexOf().
Example 1:
1 | Input: haystack = "hello", needle = "ll" |
Example 2:
1 | Input: haystack = "aaaaa", needle = "bba" |
Example 3:
1 | Input: haystack = "", needle = "" |
Constraints:
1 | 0 <= haystack.length, needle.length <= 5 * 10ˆ4 |
14. Longest Common Prefix
Write a function to find the longest common prefix string amongst an array of strings.
If there is no common prefix, return an empty string “”.
Example 1:
1 | Input: strs = ["flower","flow","flight"] |
Example 2:
1 | Input: strs = ["dog","racecar","car"] |
Constraints:
1 | 0 <= strs.length <= 200 |