USACO Ski Course Design 解题报告

这里用的是naive的方法，测试所有的高度组合（改造后的）（最低高度，最高高度）。最低高度的范围是从[low, high - 17]。low和high分别是当前的最低和最高高度。由于高度的种类很少（0~100），所以这里用一个数组(cnt)统计每个类别的高度。

/* 
ID: thestor1 
LANG: C++ 
TASK: skidesign 
*/
#include <iostream>
#include <fstream>  
#include <cmath>  
#include <cstdio>  
#include <cstring>  
#include <climits>  
#include <cassert>  
#include <string>  
#include <vector>  
#include <set>
#include <map>  
#include <queue>  
#include <stack>  
#include <algorithm>
#include <cassert>

using namespace std;

int main()
{
	ifstream fin("skidesign.in");
	ofstream fout("skidesign.out");

	int N;
	fin>>N;
	std::vector<int> cnt(101, 0);
	for (int i = 0; i < N; ++i)
	{
		int height;
		fin>>height;
		assert(0 <= height && height <= 100);
		cnt[height]++;
	}

	int low = 0, high = 100;
	
	while (cnt[low] == 0)
	{
		low++;
	}
	
	while (cnt[high] == 0)
	{
		high--;
	}

	int mincost = -1;
	for (int l = low; l <= high - 17; ++l)
	{
		int h = l + 17;
		int cost = 0;
		for (int i = low; i < l; ++i)
		{
			if (cnt[i])
			{
				cost += (l - i) * (l - i) * cnt[i];
			}
		}
		for (int i = high; i > h; --i)
		{
			if (cnt[i])
			{
				cost += (i - h) * (i - h) * cnt[i];	
			}
		}
		if (mincost < 0 || cost < mincost)
		{
			mincost = cost;
		}
	}

	fout<<max(mincost, 0)<<endl;

	fin.close();
	fout.close();
	return 0;  
}