lintcode-binarysearch-search-for-a-range

https://www.lintcode.com/problem/search-for-a-range/description

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



my turn:【has problem】
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
        
        //Sol: do the binary search twice
        //find the first postion then the last position
        
        
        int start = 0;
        int end = A.size() - 1; //index
        vector<int> bound[2];// result; //pre-initialize it with size of 2.
        
        
        //First, we consider the special case
        if(A[start] > target || A[end] < target){
            bound[0] = bound[1] = -1;
            return bound;
        }
        
        //1. search index1 --> first position
        while(start + 1 < end){
            mid = start + (end - start)*0.5;
            if[A[mid] == target]{
                end = mid;//左移
            }else if(A[mid] < target){
                start = mid;
            }else{
                end = mid
            }
        }
        
        //check two bound; // for case start + 1 = end;
        if(A[start] == target){
            bound[0] = start;
        }
        else if(A[end] == target){
            bound[0] == end;
        }else{ //start != target && end != target --> we did not find it
            bound[0] = bound[1] = -1;
            return bound;
        }
        
        
        
        //2. search index2 --> last position
        while(start + 1 < end){
            mid = start = (end - start)*0.5;
            if(A[mid] == target){
                start = mid; //右移
            }else if(A[mid] < target){
                start = mid;
            }else{
                end = mid;
            }
        }
        
        //check the bound // for last position, we check end first
        if(A[end] == target){
            bound[1] = end;
        }else if (A[start] == target){
            bound[1] = start;
        }else{
            bound[0] = bound[1] = -1;
            return bound;
        }
        
        return bound;
        
        
        
    }
};