Function exponential_search

code/chapter05/exponential_search.rs:23–39

(nums: &[i32], target: i32)

}

fn exponential_search(nums: &[i32], target: i32) -> bool {
    let size = nums.len();
    if size == 0 {
        return false;
    }

    // 逐步找到上界
    let mut high = 1usize;
    while high < size && nums[high] < target {
        high <<= 1;
    }

    //  上界的一半一定可以作为下界
    let low = high >> 1;

    binary_search(&nums[low..size.min(high+1)], target)
}

fn main() {
    let nums = [1,9,10,15,16,17,19,23,27,28,29,30,32,35];