Packing Rectangles chapter1.4

开始完全没有思路，不知如何贪心下手，后来看到这篇博主的结题报告，研究了会才搞懂

http://www.cnblogs.com/kissfinger/archive/2011/03/08/1977720.html

然后自己仿照着写，到situation5(就是第6幅图，4，5图一种情况)时还是出错了，后来想想我少考虑了一种情况

自己的是max2（a.width+b.width,c.width+d.width）,应该是max3（a.width+b.width,c.width+d.width,b.width+d.width）

/*

ID: hubiao cave

PROG: packrec

LANG: C++

*/




#include<iostream>
#include<fstream>
#include<string>
#include<algorithm>
#include<set>
using namespace std;

//#define max2(a,b) (a>b?a:b)
//#define max3(a,b,c) (a>max2(b,c)?a:max2(b,c))
//#define max4(a,b,c,d) (a>max3(b,c,d)?a:max3(b,c,d))

int max2(int a,int b)
{
    return a>b?a:b;
}
int max3(int a,int b, int c)
{
    return max2(max2(a,b),c);
}
int max4(int a,int b,int c,int d)
{
    return max2(max2(a,b),max2(c,d));
}



struct rect
{
    int width;
    int height;
};
rect rc[4];
int index[4]={0,1,2,3};

void swap(rect&);

void work(rect,rect,rect,rect);

void situ1(rect,rect,rect,rect);
void situ2(rect,rect,rect,rect);
void situ3(rect,rect,rect,rect);
void situ4(rect,rect,rect,rect);
void situ5(rect,rect,rect,rect);

bool operator<(const rect& rc1,const rect&rc2)
{
    return rc1.width<rc2.width;
}

void update(int,int);

int miniarea=999999;
std::set<rect> sr;

int main()

{

    ifstream fin("packrec.in");
    ofstream fout("packrec.out");
    for(int i=0;i<4;i++)
    {
        fin>>rc[i].height>>rc[i].width;
    }

    for(int i=0;i<2;i++)
    {
        swap(rc[0]);
        for(int j=0;j<2;j++)
        {
            swap(rc[1]);
            for(int m=0;m<2;m++)
            {
                swap(rc[2]);
                for(int n=0;n<2;n++)
                {
                    swap(rc[3]);
                    
                    do 
                    {
                        work(rc[index[0]],rc[index[1]],rc[index[2]],rc[index[3]]);

                    } while (std::next_permutation(index,index+4));
                }
            }
        }
    }

    fout<<miniarea<<endl;
    for(set<rect>::iterator it=sr.begin();it!=sr.end();it++)
    {
        fout<<(*it).width<<" "<<(*it).height<<endl;
    }
    return 0;


}

void swap(rect&rc1)
{
    int n=rc1.height;
    rc1.height=rc1.width;
    rc1.width=n;
}

void situ1(rect a,rect b,rect c,rect d)
{
    int maxh=max4(a.height,b.height,c.height,d.height);
    int totalw=a.width+b.width+c.width+d.width;
    update(maxh,totalw);
}

void situ2(rect a,rect b,rect c,rect d)
{
    int maxw=max2(d.width,a.width+b.width+c.width);
    int maxh=max3(a.height,b.height,c.height)+d.height;
    update(maxh,maxw);
}

void situ3(rect a,rect b,rect c,rect d)
{
    int maxw=c.width+max2(a.width+b.width,d.width);
    int maxh=max2(max2(a.height,b.height)+d.height,c.height);
    update(maxh,maxw);
}

void situ4(rect a,rect b,rect c,rect d)
{
    int maxw=a.width+c.width+max2(b.width,d.width);
    int maxh=max3(a.height,c.height,b.height+d.height);
    update(maxh,maxw);
}

void situ5(rect a,rect b,rect c,rect d)
{
    int maxh=max2(a.height+d.height,b.height+c.height);
    int maxw;
    if(c.height>=a.height+d.height)
    {
        maxw=max2(max2(a.width,d.width)+c.width,b.width);
    }
    else
    {
        if(c.height>=d.height)
        {
            maxw=max3(a.width+b.width,c.width+d.width,a.width+c.width);
        }
        if(c.height<d.height&&c.height+b.height>d.height)
        {
            maxw=max3(a.width+b.width,c.width+d.width,b.width+d.width);
        }
        if(b.height+c.height<=d.height)
        {
            maxw=max2(a.width,max2(b.width,c.width)+d.width);
        }


    }
    update(maxh,maxw);
}


void update(int wid,int height)
{
    rect rc1;
    int area=wid*height;

    if(wid>height)
    {
        int temp=height;
        height=wid;
        wid=temp;
    }
    rc1.height=height;
    rc1.width=wid;

    if(area<miniarea)
    {
        sr.clear();
        sr.insert(rc1);
        miniarea=area;
        return;
    }
    if(area==miniarea)
    {
        sr.insert(rc1);
        return;
    }
    return;
    

}

void work(rect a,rect b,rect c,rect d)
{
    situ1(a,b,c,d);
    situ2(a,b,c,d);
    situ3(a,b,c,d);
    situ4(a,b,c,d);
    situ5(a,b,c,d);

}