## 162. Find Peak Element

A peak element is an element that is strictly greater than its neighbors.

Given an integer array `nums`, find a peak element, and return its index. If the array contains multiple peaks, return the index to any of the peaks.

You may imagine that `nums[-1] = nums[n] = -∞`.

Example 1:

```Input: nums = [1,2,3,1]
Output: 2
Explanation: 3 is a peak element and your function should return the index number 2.```

Example 2:

```Input: nums = [1,2,1,3,5,6,4]
Output: 5
Explanation: Your function can return either index number 1 where the peak element is 2, or index number 5 where the peak element is 6.```

Constraints:

• `1 <= nums.length <= 1000`
• `-231 <= nums[i] <= 231 - 1`
• `nums[i] != nums[i + 1]` for all valid `i`.

Follow up: Could you implement a solution with logarithmic complexity?

## Rust Solution

``````struct Solution;

impl Solution {
fn find_peak_element(nums: Vec<i32>) -> i32 {
let mut l = 0;
let mut h = nums.len() - 1;
while l < h {
let m1 = l + (h - l) / 2;
let m2 = m1 + 1;
if nums[m1] < nums[m2] {
l = m2;
} else {
h = m1;
}
}
l as i32
}
}

#[test]
fn test() {
let nums = vec![1, 2, 3, 1];
let res = 2;
assert_eq!(Solution::find_peak_element(nums), res);
let nums = vec![1, 2, 1, 3, 5, 6, 4];
let res = 5;
assert_eq!(Solution::find_peak_element(nums), res);
}
``````

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