网络流/费用流/二分图最大权匹配
拆点费用流求最大权匹配……妈蛋BZOJ上是数据出错了吗？为什么我拿zyf和Hzwer的代码也交不过去……害我白白WA了那么多次
1 //BZOJ 2661
2 #include<cmath>
3 #include<vector>
4 #include<cstdio>
5 #include<cstring>
6 #include<cstdlib>
7 #include<iostream>
8 #include<algorithm>
9 #define rep(i,n) for(int i=0;i<n;++i)
10 #define F(i,j,n) for(int i=j;i<=n;++i)
11 #define D(i,j,n) for(int i=j;i>=n;--i)
12 #define pb push_back
13 using namespace std;
14 inline int getint(){
15 int v=0,sign=1; char ch=getchar();
16 while(ch<‘0‘||ch>‘9‘){ if (ch==‘-‘) sign=-1; ch=getchar();}
17 while(ch>=‘0‘&&ch<=‘9‘){ v=v*10+ch-‘0‘; ch=getchar();}
18 return v*sign;
19 }
20 const int N=2010,M=2000000,INF=~0u>>2;
21 typedef long long LL;
22 /******************tamplate*********************/
23 int n,m,a,b,ans,flow;
24 inline int gcd(int a,int b){return b ? gcd(b,a%b) : a;}
25 bool judge(int x,int y){
26 int q=x*x-y*y,s=sqrt(q);
27 if (s*s==q && gcd(y,s)==1) return 1;
28 return 0;
29 }
30 struct edge{int from,to,v,c;};
31 struct Net{
32 edge E[M];
33 int head[N],next[M],cnt;
34 void ins(int x,int y,int z,int c){
35 E[++cnt]=(edge){x,y,z,c};
36 next[cnt]=head[x]; head[x]=cnt;
37 }
38 void add(int x,int y,int z,int c){
39 ins(x,y,z,c); ins(y,x,0,-c);
40 }
41 int from[N],Q[M],d[N],S,T;
42 bool inq[N];
43 bool spfa(){
44 int l=0,r=-1;
45 F(i,0,T) d[i]=INF;
46 d[S]=0; Q[++r]=S; inq[S]=1;
47 while(l<=r){
48 int x=Q[l++];
49 inq[x]=0;
50 for(int i=head[x];i;i=next[i])
51 if(E[i].v>0 && d[x]+E[i].c<d[E[i].to]){
52 d[E[i].to]=d[x]+E[i].c;
53 from[E[i].to]=i;
54 if (!inq[E[i].to]){
55 Q[++r]=E[i].to;
56 inq[E[i].to]=1;
57 }
58 }
59 }
60 return d[T]!=INF;
61 }
62 void mcf(){
63 int x=INF,y,z;
64 for(int i=from[T];i;i=from[E[i].from]){
65 // if (E[i].from==S) y=E[i].to;
66 // if (E[i].to==T) z=E[i].from-b;
67 x=min(x,E[i].v);
68 }
69 for(int i=from[T];i;i=from[E[i].from]){
70 E[i].v-=x;
71 E[i^1].v+=x;
72 }
73 flow+=x;
74 ans+=x*d[T];
75 }
76 void init(){
77 scanf("%d%d",&a,&b);
78 cnt=1; S=0; T=2001;
79 F(i,a,b){
80 add(S,i,1,0);
81 add(i+b,T,1,0);
82 F(j,a,i-1)
83 if(judge(i,j)) add(i,j+b,1,-i-j);
84 }
85 while(spfa()) mcf();
86 printf("%d %d",flow,-ans);
87 }
88 }G1;
89
90 int main(){
91 #ifndef ONLINE_JUDGE
92 freopen("2661.in","r",stdin);
93 freopen("2661.out","w",stdout);
94 #endif
95 G1.init();
96 return 0;
97 }
时间： 2024-08-04 16:02:27