UVA-714-二分+贪心

　　题意：K个人复制M本书,每本书有Pi页,要求每个人都能分到至少一本书,如果分到多本书籍,分到的书籍编号是连续的,并且K个人里面分到的书籍总页数最大的那个人总数最小.

如果有多组解,保证 K1 < K2 < K3.....

解法:

二分最小的最大值,答案范围肯定是(L=0)  -  (R=total_page), 假设答案是ans= (L+R)/2,假设当前ans是正确的,那么给K个人分配,如果成功那么最优解的范围是 ans - R，

如果不成功,那么最优解是0 - ans,

#include "pch.h"
#include <string>
#include<iostream>
#include<map>
#include<memory.h>
#include<vector>
#include<algorithm>
#include<queue>
#include<vector>
#include<stack>
#include<math.h>
#include<iomanip>

namespace cc
{
	using std::cout;
	using std::endl;
	using std::cin;
	using std::map;
	using std::vector;
	using std::string;
	using std::sort;
	using std::priority_queue;
	using std::greater;
	using std::vector;
	using std::swap;
	using std::stack;

	class Point
	{

	public: int l, r, len;
			Point() {};
			Point(int x, int y) :l(x), r(y) {
				if (l < 0)
					this->len = r;
				else
					this->len = r - l; 

			};

			int operator < (Point& p)
			{
				int l1 = p.l;
				int l2 = this->l;
				if (l1 < 0)
					l1 = 0;
				if (l2 < 0)
					l2 = 0;
				if (l1 < l2)
					return 0;
				if (l1 == l2)
					return p.len < this->len;
				return 1;
			}

	};

	constexpr int N = 502;
	int M, K;
	int cases;
	int assignTotal = 0;
	//由后往前
	int assignIndex[N];
	long long pages[N];
	long long totalPages = 0;
	int avg = 0;

	/*
	*
	*ok return 1
	*/
	int cal(long long cur)
	{
		int ass[N];
		int assIndex = 0;
		long long curTotal = 0;
		int i = -1;
		for (i=M-1;i>=0;i--)
		{
			if (pages[i] > cur)
				return 0;
			if (curTotal+pages[i] > cur || (i + 1 < K - assIndex))
			{
				ass[assIndex++] = i+1;
				if (assIndex > K)
					return 0 ;
				curTotal = 0;
				curTotal += pages[i];
				continue;
			}

			curTotal += pages[i];
		}
		if (assIndex != K-1)
			return 0;
		ass[assIndex++] = 0;
		//assIndex = K
		//copy
		memcpy(assignIndex,ass,sizeof(int)*assIndex);
		assignTotal = assIndex;
		return 1;
	}

	void solve()
	{

		cin >> cases;
		while (cases--)
		{
			totalPages = 0;
			avg = 0;
			assignTotal = 0;
			cin >> M >> K;
			for(int i=0;i<M;i++)
			{
				cin >> pages[i];
				totalPages += pages[i];
			}
			long long l = 0, r = totalPages;
			while (l < r-1)
			{
				long long mid = (l + r) / 2;
				int ok = cal(mid);
				if (ok)
				{
					//mid是最优
					r = mid;
				}
				else
				{
					//mid不是最优
					l = mid;
				}
			}
			//print
			int cpi = assignTotal-2;

			for (int  i=0;i < M;i++)
			{

				if (cpi >= 0 && i == assignIndex[cpi])
				{
					cout << " /";
					--cpi;
				}
				if (i == 0)
					cout << pages[i];
				else
					cout << " " << pages[i];
			}
			cout << endl;

		}

	}

};

int main()
{

#ifndef ONLINE_JUDGE
	freopen("d://1.text", "r", stdin);
#endif // !ONLINE_JUDGE
	cc::solve();

	return 0;
}