35 Search Insert Position

Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.

You may assume no duplicates in the array.

Here are few examples.
[1,3,5,6], 5 → 2
[1,3,5,6], 2 → 1
[1,3,5,6], 7 → 4
[1,3,5,6], 0 → 0

分析及代码

二分搜索，O(logn)，没什么好说的，做2d matrix search顺手写了一下

public int searchInsert(int[] nums, int target) {
    if(nums.length == 0) {
        return 0;
    }
    int len = nums.length;
    int l = 0;
    int r = len - 1;
    while(l <= r) {
        int mid = l + (r - l) / 2;
        if(nums[mid] == target) {
            return mid;
        } else if(nums[mid] < target) {
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }
    return l;
}