# hdu 2282 Chocolate (二分图最优匹配,KM算法)

Posted by 111qqz on Thursday, June 2, 2016

## TOC

hdu 2282 题目链接

``````/* ***********************************************
Author :111qqz
Created Time :2016年06月01日 星期三 21时12分48秒
File Name :code/hdu/2282.cpp
************************************************ */

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
#include <ctime>
#define fst first
#define sec second
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define ms(a,x) memset(a,x,sizeof(a))
typedef long long LL;
#define pi pair < int ,int >
#define MP make_pair

using namespace std;
const double eps = 1E-8;
const int dx4[4]={1,0,0,-1};
const int dy4[4]={0,-1,1,0};
const int inf = 0x3f3f3f3f;
const int N=505;
int n,m;
int p[N]; //p[i]表示第i个巧克力的初始位置。
int a[N];
int lx[N],ly[N];
bool visx[N],visy[N];
int slk[N];
int w[N][N];

void init()
{
m = 0 ;
ms(p,-1);
}

int calw(int x,int y)
{
int res = abs(x-y);
res = min(res,n-res);
//cout<<"res:"<<res<<endl;
return -res;
}

bool find( int u)
{
visx[u] = true;

for ( int v = 1 ; v <= n ; v++)
{
if (visy[v]) continue;
int tmp = lx[u] + ly[v] - calw(p[u],v);

if (tmp==0)
{
visy[v] = true;
{
return true;
}
}else if (tmp<slk[v]) slk[v] = tmp;
}
return false;
}
int KM()
{
ms(lx,0xc0);
ms(ly,0);

for ( int i = 1 ; i <= m ; i++)
for ( int j = 1 ; j <= n ;j++)
lx[i] = max(lx[i],calw(p[i],j));
//   for ( int i = 1 ; i <= m ; i++) cout<<"p[i]:"<<p[i]<<endl;
//   for ( int i = 1 ; i <= m ; i++) cout<<"lx[i]:"<<lx[i]<<endl;

for ( int i = 1 ; i <= m ; i++)
{
ms(slk,0x3f);

while (1)
{
ms(visx,false);
ms(visy,false);

if (find(i)) break;

int d = inf;

for ( int j = 1 ; j <= n ; j++)
if (!visy[j]&&slk[j]<d) d = slk[j];

for ( int j = 1 ; j <= m ; j++)
if (visx[j]) lx[j]-=d;
for ( int j = 1 ; j <= n ;j++)
if (visy[j]) ly[j]+=d ; else slk[j]-=d;
}
}
int res = 0 ;
for ( int i = 1 ; i <= n ; i++)

return -res;

}
int main()
{
#ifndef  ONLINE_JUDGE
freopen("code/in.txt","r",stdin);
#endif

while (scanf("%d",&n)!=EOF)
{

init();
for ( int i = 1 ; i <= n ;i++)
{
int x;
scanf("%d",&x);
a[i] = x;
while (x--)
{
p[++m] = i;
}
}
int ans = KM();

printf("%d\n",ans);

}

#ifndef ONLINE_JUDGE
fclose(stdin);
#endif
return 0;
}
``````

「真诚赞赏，手留余香」