Given a sorted (in ascending order) integer array nums of n elements and a target value, write a function to search target in nums. If target exists, then return its index, otherwise return -1.
Example 1:
Input: nums = [-1,0,3,5,9,12], target = 9
Output: 4
Explanation: 9 exists in nums and its index is 4
Example 2:
Input: nums = [-1,0,3,5,9,12], target = 2
Output: -1
Explanation: 2 does not exist in nums so return -1
Note:
- You may assume that all elements in
numsare unique. nwill be in the range[1, 10000].- The value of each element in
numswill be in the range[-9999, 9999].
这道题就是最基本的二分搜索法了，这是博主之前总结的LeetCode Binary Search Summary 二分搜索法小结的四种之中的第一类，也是最简单的一类，写法什么很模版啊，注意right的初始化值，还有while的循环条件，以及right的更新值，这三点不同的人可能会有不同的写法，选一种自己最习惯的就好啦，参见代码如下：
class Solution {
public:
int search(vector<int>& nums, int target) {
int left = 0, right = nums.size();
while (left < right) {
int mid = left + (right - left) / 2;
if (nums[mid] == target) return mid;
else if (nums[mid] < target) left = mid + 1;
else right = mid;
}
return -1;
}
};
类似题目：
Search in a Sorted Array of Unknown Size
参考资料：
https://leetcode.com/problems/binary-search
LeetCode All in One 题目讲解汇总(持续更新中…)
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