leetcode 81 rust

题目

编程语言

rust

注意点

二分法和33题相似，仅当有数字重复时进行不同的判断

代码

pub fn search(nums: Vec<i32>, target: i32) -> bool {
    let mut left = 0_i32;
    let mut right = (nums.len() as i32) - 1;
    let mut mid;
    while left <= right {
        mid = left + ((right - left) >> 1);
        if nums[mid as usize] == target {
            return true;
        }
        // nums[left] == nums[mid] 意味着从nums[mid]到nums[right]到nums[left]的值都相等
        if nums[mid as usize] == nums[left as usize] {
            left += 1;
            continue;
        }
        match nums[mid as usize].cmp(&nums[left as usize]) {
            // left和mid 落在同一数组中
            std::cmp::Ordering::Greater | std::cmp::Ordering::Equal => {
                // left，mid，right，target在同一数组中
                if nums[mid as usize] > target && target >= nums[left as usize] {
                    right = mid - 1;
                // target落在mid和right中间
                }else if nums[mid as usize] < target || target < nums[left as usize] {
                    left = mid + 1;
                }
            },
            // left和mid 落在两个数组中
            std::cmp::Ordering::Less => {
                // left，mid，right，target在同一数组中
                if nums[mid as usize] < target && target <= nums[right as usize] {
                    left = mid + 1;
                // target落在left和mid中间
                }else if nums[mid as usize] > target || target > nums[right as usize] {
                    right = mid - 1;
                }
            },
        }
    }
    false
}

测试

#[cfg(test)]
mod tests{
    use super::*;
    #[test]
    fn test_exist(){
        assert_eq!(search(vec![2,5,6,0,0,1,2],0),true);
    }
    #[test]
    fn test_not_exist(){
        assert_eq!(search(vec![2,5,6,0,0,1,2],3),false);
    }
    #[test]
    fn test_null(){
        assert_eq!(search(vec![1],0),false);
    }
}