Given a sorted array of integers, find the starting and ending position of a given target value.
Your algorithm's runtime complexity must be in the order of O(log n).
If the target is not found in the array, return [-1, -1]
.
For example,
Given [5, 7, 7, 8, 8, 10]
and target value 8,
return [3, 4]
.
class Solution {
public:
vector<
int> searchRange(
int A[],
int n,
int target)
{
int left=searchleft(A,
0,n-
1,target);
int right=searchright(A,
0,n-
1,target);
vector<
int> v;
v.push_back(left);
v.push_back(right);
return v;
}
int searchleft(
int A[],
int l,
int r,
int target)
{
if(l>r)
return -
1;
int m=(l+r)/
2;
if(A[m]==target)
{
int index=searchleft(A,l,m-
1,target);
if(index==-
1)
return m;
else
return index;
}
else
if(A[m]>target)
return searchleft(A,l,m-
1,target);
else
return searchleft(A,m+
1,r,target);
}
int searchright(
int A[],
int l,
int r,
int target)
{
if(l>r)
return -
1;
int m=(l+r)/
2;
if(A[m]==target)
{
int index=searchright(A,m+
1,r,target);
if(index==-
1)
return m;
else
return index;
}
else
if(A[m]>target)
return searchright(A,l,m-
1,target);
else
return searchright(A,m+
1,r,target);
}
};