34. Search for a Range
Problem's Link
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Mean:
给定一个有序数组和一个数k,求k在这个数组中的起始下标和结束下标.
analyse:
二分查找.
Time complexity: O(N)
view code
/**
* -----------------------------------------------------------------
* Copyright (c) 2016 crazyacking.All rights reserved.
* -----------------------------------------------------------------
* Author: crazyacking
* Date : 2016-03-01-22.03
*/
#include <queue>
#include <cstdio>
#include <set>
#include <string>
#include <stack>
#include <cmath>
#include <climits>
#include <map>
#include <cstdlib>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
using namespace std;
typedef long long( LL);
typedef unsigned long long( ULL);
const double eps( 1e-8);
class Solution
{
public :
vector < int > searchRange( vector < int >& nums , int target)
{
vector < int > ret;
int len = nums . size();
int low = 0 , high = len - 1;
while( low <= high)
{
int mid =( low + high) >> 1;
if( target < nums [ mid ])
high = mid - 1;
else if( target > nums [ mid ])
low = mid + 1;
else
{
int frontIndex = mid , backIndex = mid;
while( frontIndex - 1 >= 0 && nums [ frontIndex ] == nums [ frontIndex - 1 ])
-- frontIndex;
while( backIndex + 1 < len && nums [ backIndex ] == nums [ backIndex + 1 ])
++ backIndex;
ret . push_back( frontIndex);
ret . push_back( backIndex);
return ret;
}
}
ret . push_back( - 1);
ret . push_back( - 1);
return ret;
}
};
int main()
{
Solution solution;
int n , k;
while( cin >>n >> k)
{
vector < int > ve;
for( int i = 0; i <n; ++ i)
{
int tempVal;
cin >> tempVal;
ve . push_back( tempVal);
}
ve = solution . searchRange( ve , k);
for( auto p: ve)
cout <<p << endl;
}
return 0;
}
/*
*/
* -----------------------------------------------------------------
* Copyright (c) 2016 crazyacking.All rights reserved.
* -----------------------------------------------------------------
* Author: crazyacking
* Date : 2016-03-01-22.03
*/
#include <queue>
#include <cstdio>
#include <set>
#include <string>
#include <stack>
#include <cmath>
#include <climits>
#include <map>
#include <cstdlib>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
using namespace std;
typedef long long( LL);
typedef unsigned long long( ULL);
const double eps( 1e-8);
class Solution
{
public :
vector < int > searchRange( vector < int >& nums , int target)
{
vector < int > ret;
int len = nums . size();
int low = 0 , high = len - 1;
while( low <= high)
{
int mid =( low + high) >> 1;
if( target < nums [ mid ])
high = mid - 1;
else if( target > nums [ mid ])
low = mid + 1;
else
{
int frontIndex = mid , backIndex = mid;
while( frontIndex - 1 >= 0 && nums [ frontIndex ] == nums [ frontIndex - 1 ])
-- frontIndex;
while( backIndex + 1 < len && nums [ backIndex ] == nums [ backIndex + 1 ])
++ backIndex;
ret . push_back( frontIndex);
ret . push_back( backIndex);
return ret;
}
}
ret . push_back( - 1);
ret . push_back( - 1);
return ret;
}
};
int main()
{
Solution solution;
int n , k;
while( cin >>n >> k)
{
vector < int > ve;
for( int i = 0; i <n; ++ i)
{
int tempVal;
cin >> tempVal;
ve . push_back( tempVal);
}
ve = solution . searchRange( ve , k);
for( auto p: ve)
cout <<p << endl;
}
return 0;
}
/*
*/