Q:
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
nums
are unique.
n
will be in the range [1, 10000]
.
- The value of each element in
nums
will be in the range [-9999, 9999]
.
A:
a,b is (a,b] 左闭开右开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:
nums
= [-1,0,3,5,9,12], target
= 9
Output: 4
Explanation: 9 exists in nums
and its index is 4
nums
= [-1,0,3,5,9,12], target
= 2
Output: -1
Explanation: 2 does not exist in nums
so return -1
nums
are unique.n
will be in the range [1, 10000]
.nums
will be in the range [-9999, 9999]
.class Solution { public: int search(vector<int>& nums, int target) { int n = nums.size(); if(n==0) return -1; int a=0, b=n; while(a<b) { int mid = (a+b)/2; if(nums[mid] == target) { return mid; }else if(nums[mid] < target) { a = mid+1; }else { b = mid; } } return -1; } };
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