力扣35.搜索插入位置

#include <iostream>
#include <vector>

using namespace std;

class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        int n = nums.size();
        int left = 0, right = n - 1, ans = n;
        while (left <= right) {
            int mid = ((right - left) >> 1) + left;//如果不加left那么就只要right与left
            if (target <= nums[mid]) {
                ans = mid;
                right = mid - 1;
            }
            else {
                left = mid + 1;
            }
        }
        return ans;
    }
};

int main() {
    Solution solution;
    vector<int> nums = { 1, 3, 5, 6 ,9};
    int target = 7;
    int result = solution.searchInsert(nums, target);
    cout << "输出: " << result << endl;
    return 0;
}

分析：利用二分法，不停的逼近这个值，如果目标值小于二分法求取的中间索引的这个值，那么首先保存这个索引值，第二右边的索引值等于mid-1,就是向左去夹近。如果target大于这个值则左边界+1，每次mid的值是right-left的和>>1并且加上lef