035_Search_Insert_Position.md

35. Search Insert Position

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Description

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

Javascript

解法一：直接查找，O(n)。

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number}
 */
var searchInsert = function(nums, target) {
    if (nums.indexOf(target) !== -1) {
        return nums.indexOf(target);
    }
    var i;
    for (i = 0; i < nums.length; i++) {
        if (nums[i] > target) {
            return i;
        }
    }
    return nums.length;
};

Java

解法二：二分查找，O(logn)。

public class Solution {
    public int searchInsert(int[] nums, int target) {
        int mid, i = 0, j = nums.length - 1;
        while (i <= j) {
            mid = (i + j) / 2;
            if (nums[mid] == target) {
                return mid;
            } else if (nums[mid] > target) {
                j = mid - 1;
            } else {
                i = mid + 1;
            }
        }
        return i;
    }
}