28. 搜索二维矩阵二分法

[[1, 3, 5, 7],
  [10, 11, 16, 20],
  [23, 30, 34, 50]
]
给出 target = 3，返回 true

  bool searchMatrix(vector<vector<int>> &matrix, int target) {
        int row_sz=matrix.size();
        if(row_sz<1)
        return false;
        int col_sz=matrix[0].size();
        if(target<matrix[0][0]||target>matrix[row_sz-1][col_sz-1])
        return false;
        int high=0;
        int low=row_sz-1;
        int mid;
        while(high<=low)
        {
            mid=high+(low-high)/2;
            if(matrix[mid][0]==target||matrix[mid][col_sz-1]==target)
            return true;
            else if(matrix[mid][0]<target&&matrix[mid][col_sz-1]>target)   //刚好落在这个区间
            {
                break;
            }
            else if(matrix[mid][0]>target)
            {
                low=mid-1;
            }
            else if(matrix[mid][col_sz-1]<target)
            {
                high=mid+1;
            }
        }
        
        int left=0;
        int right=col_sz-1;
        int col_mid;
        while(left<right)
        {
            col_mid=left+(right-left)/2;
            if(matrix[mid][col_mid]==target)
            {
                return true;
            }
            else if(matrix[mid][col_mid]<target)
            {
                left=col_mid+1;      //就是这里，col_mid写成Mid了，导致死循环，气的很
            }
            else if(matrix[mid][col_mid]>target)
            {
                right=col_mid-1;
            }
        }
        return false;
       // write your code here
    }