leetcode_rust/
find_peak_element.rs

1#![allow(dead_code)]
2
3// binary search
4pub fn find_peak_element(nums: Vec<i32>) -> i32 {
5    let mut left = 0;
6    let mut right = nums.len() - 1;
7    if nums.len() < 2 {
8        return 0;
9    }
10    while left < right {
11        let mid = (right + left) / 2;
12        if mid > 0 && mid + 1 < nums.len() {
13            if nums[mid] > nums[mid - 1] && nums[mid] > nums[mid + 1] {
14                return mid as i32;
15            }
16            if nums[mid] < nums[mid - 1] {
17                right = mid - 1;
18            } else {
19                left = mid + 1;
20            }
21        } else if mid == 0 && nums[0] > nums[1] {
22            return mid as i32;
23        } else if mid == nums.len() - 1 && nums[mid - 1] < nums[mid] {
24            return mid as i32;
25        } else {
26            left = mid + 1;
27        }
28    }
29
30    return left as i32;
31}
32
33#[cfg(test)]
34mod tests {
35    use super::*;
36
37    #[test]
38    fn test1() {
39        assert_eq!(find_peak_element(vec![2, 1, 2]), 0);
40        assert_eq!(find_peak_element(vec![2, 1]), 0);
41        assert_eq!(find_peak_element(vec![1, 2]), 1);
42        assert_eq!(find_peak_element(vec![1, 2, 3]), 2);
43        assert_eq!(find_peak_element(vec![1, 2, 3, 1]), 2);
44        assert_eq!(find_peak_element(vec![1, 2, 1, 3, 5, 6, 4]), 5);
45    }
46}
leetcode_rust/find_peak_element.rs

leetcode_rust/
find_peak_element.rs
