Problem description:
There are N Monkeys and N bananas are placed in a straight line. Each monkey want to have a banana, if two monkeys want to own the same banana, there will be a fight! A monkey can stay at his position, move one step right from x to x + 1, or move one step left from x to x -1. Any of these moves consumes 1 second. Assign monkeys to banana so that not monkey fight each other and the time when the last monkey gets a banana is minimized.
Input:
The input contain two arrays of int. The first array is the positions of monkeys. The second array is the positions of bananas.
Output:
The output is a int, which is the time(in seconds) it takes when all bananas are assigned to monkeys.
Sample input:
1 3 6
2 4 6
Sample output:
1
Sample explanation:
Assign monkey at position 1 to banana at position 2. (1 second)
Assign monkey at position 3 to banana at position 4. (1 second)
Assign monkey at position 6 to banana at position 6. (0 second)
Overall time is max(1, 1, 0) = 1 second.
方法1,通过数组实现:
#include <iostream>
#include<algorithm>
using namespace std;
int mk[10000000], bn[10000000];//mk猴子,bn香蕉
int main()
{
int count=0;//当前最大距离差绝对值
int i=0;
//依次输入猴子位置,回车结束当前行输入
while(cin >> mk[i])
{
i++;
if (cin.get() == '\n')
break;
}
sort(mk,mk+i);
//依次输入香蕉位置,回车结束当前行输入
i = 0;
while (cin >> bn[i])
{
i++;
if (cin.get() == '\n')
break;
}
sort(bn,bn+i);
//依次比较对应下标位置 猴子移动到对应香蕉 需要的绝对差值,最后选最大的为时间差值
for (int j = 0; j < i; j++)
{
if(abs(mk[j] - bn[j])>count)
count=abs(mk[j]-bn[j]);
}
cout << count;
return 0;
}
方法2,通过vector实现:
#include <iostream>
#include<vector>
#include<algorithm>
using namespace std;
int main()
{
vector<int> mk, bn;//猴子,香蕉
int count=0;//当前最大距离差绝对值
int i;
while (cin >> i)
{
mk.push_back(i);
if (cin.get() == '\n')
break;
}
sort(mk.begin(), mk.end());
while (cin >> i)
{
bn.push_back(i);
if (cin.get() == '\n')
break;
}
sort(bn.begin(), bn.end());
for (int j = 0; j < int(mk.size()); j++)
{
if(abs(mk[j] - bn[j])>count)
count = abs(mk[j] - bn[j]);
}
cout << count;
return 0;
}
两种方法在UOJ平台的测试结果对比:
第一个是使用vector ,第二个是使用数组
Vector虽然是动态数组,但是本质上和数组没什么区别,频繁的销毁新建,效率很低,所以正确的做法是新建vector的时候初始化一个合适的大小。vector默认创建给一个初始大小,然后通常按1.5倍增长,因此,此测试例中 vector所占内存 比 自己设定的固定长度数组 内存占用大,耗时间长!