61. Search for a Range

Code(Language:C++)

class Solution {
public:
    /**
     * @param A: an integer sorted array
     * @param target: an integer to be inserted
     * @return: a list of length 2, [index1, index2]
     */
    vector<int> searchRange(vector<int> &A, int target) {
        // write your code here
        const int size = A.size(); 
        vector<int> res(2, -1); 
        if(size == 0){
            return res; 
        }
        int start = 0; 
        int end = size - 1; 
        while(start + 1 < end){
            int mid = start + (end - start) / 2; 
            if(A[mid] >= target){
                end = mid; 
            }
            else{
                start = mid; 
            }
        }
        if(A[start] == target){
            res[0] = start; 
        }
        else if(A[end] == target){
            res[0] = end; 
        }
        else{
            return res; 
        }
        start = 0; 
        end = size - 1; 
        while(start + 1 < end){
            int mid = start + (end - start) / 2; 
            if(A[mid] > target){
                end = mid; 
            }
            else{
                start = mid; 
            }
        }
        if(A[end] == target){
            res[1] = end; 
        }
        else if(A[start] == target){
            res[1] = start; 
        }
        return res; 
        
    }
};