1 class Solution { 2 public: 3     string getRange(int start, int end) { 4         ostringstream oss; 5         if (start == end) { 6             oss << start; 7         } else { 8             oss << start << "->" << end; 9         }10         return oss.str();11     }12     vector
     
       findMissingRanges(int A[], int n, int lower, int upper) {13         vector
      
        result;14         int prev = lower - 1;15         for (int i = 0; i < n; i++) {16             if (A[i] - prev > 1) {17                 result.push_back(getRange(prev+1, A[i]-1));18             }19             prev = A[i];20         }21         if (upper - prev > 0) result.push_back(getRange(prev+1, upper));22         return result;23         24     }25 };