bzoj2879: [Noi2012]美食节

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxk = 100 + 10;
const int maxn = 10000 + 10;
const int maxm = 2000000 + 10;
const int inf = 0x3f3f3f3f;
int g[maxn],v[maxm],next[maxm],c[maxm],f[maxm],eid;
int n,m,res,p,vid,S,T;
int id[maxk][1010],cnt[maxk];
int a[maxk][maxk];
int q[maxm],l,r,u;
bool inque[maxn];
int dist[maxn],pre[maxn];

void addedge(int a,int b,int F,int C) {
    v[eid]=b; f[eid]=F; c[eid]=C;  next[eid]=g[a]; g[a]=eid++;    
    v[eid]=a; f[eid]=0; c[eid]=-C; next[eid]=g[b]; g[b]=eid++;
}

void build() {
    memset(g,-1,sizeof(g));
    scanf("%d%d",&n,&m);
    vid=n; S=0; T=maxn-10;
    for(int i=1,x;i<=n;i++) {
        scanf("%d",&x);
        addedge(S,i,x,0);
        p+=x;
    }
    for(int i=1;i<=m;i++) {
        id[i][++cnt[i]]=++vid;
        addedge(id[i][cnt[i]],T,1,0);
    }
    for(int i=1;i<=n;i++)
    for(int j=1;j<=m;j++) {
        scanf("%d",&a[i][j]);
        addedge(i,id[j][cnt[j]],1,a[i][j]);        
    }
}

void augment() {
    int aug=inf,cur=0;
    for(int i=T;i!=S;i=v[pre[i]^1]) aug=min(aug,f[pre[i]]);
    for(int i=T;i!=S;i=v[pre[i]^1]) {
        f[pre[i]]-=aug;
        f[pre[i]^1]+=aug;
        cur+=aug*c[pre[i]];
    }
    res+=cur;
}

int SPFA() {
    memset(dist,0x3f,sizeof(dist));    
    dist[S]=0;
    q[r++]=S; 
    while(l<r) {
        inque[u=q[l++]]=0;
        for(int i=g[u];~i;i=next[i]) if(f[i]&&dist[v[i]]>dist[u]+c[i])    {
            dist[v[i]]=dist[u]+c[i];
            pre[v[i]]=i;
            if(!inque[v[i]]) inque[q[r++]=v[i]]=1;
        }
    }
    //printf("test %d\n",dist[T]);
    augment();
    return v[pre[T]^1];
}

void alter(int pos) {
    int x;
    for(int i=1;i<=m;i++) if(id[i][cnt[i]]==pos) {x=i; break;}
    id[x][++cnt[x]]=++vid;
    addedge(id[x][cnt[x]],T,1,0);
    for(int i=1;i<=n;i++) addedge(i,id[x][cnt[x]],1,a[i][x]*cnt[x]);
}

void solve() {
    res=0;
    for(int i=1;i<=p;i++) alter(SPFA());
    printf("%d\n",res);
}

int main() {
    build();
    solve();    
    return 0;
}