[BZOJ 3218]a + b Problem

又是一道主席树优化网络流的好题

按约大爷的教导，源点为白，汇点为黑，搞成最小割

发现暴力连边要爆炸，但是要连的点在线段树中都构成了一个区间，果断主席树优化之

为什么不用一般线段树？

因为要满足 j<i ，这里的可持久化并不是为了查询过去的值，而是为了保留过去的值不与后来弄混～

如果有两个点的 a[i] 相同在线段树里怎么搞？

很简单，从 a[i] 向 a[j] 连一条 inf 的流即可

不过——为什么题目名字那么坑啊啊啊啊啊啊？！！！！！

　　　　这种题是不是非要来卡空间不然不痛快是吗？！！！！！

#include <cstdio>
#include <cstring>
const int sizeOfSegment=500005;
const int sizeOfEdge=1000001;
const int sizeOfPoint=500005;
const int sizeOfCell=5005;
const int inf=1000000000;

inline int min(int, int);
inline int getint();
inline void putint(int);

int S, T;
int V;
int n;
int a[sizeOfCell], b[sizeOfCell], w[sizeOfCell], l[sizeOfCell], r[sizeOfCell], p[sizeOfCell];

struct edge {int point, flow; edge * next, * pair;};
edge memory_edge[sizeOfEdge], * port_edge=memory_edge;
edge * e[sizeOfPoint];
inline edge * newedge(int, int, edge * );
inline void link(int, int, int);
int h[sizeOfPoint], gap[sizeOfPoint];
inline bool bfs();
inline int isap();

struct seg {int p; seg * l, * r;};
seg memory_seg[sizeOfSegment], * port_seg=memory_seg;
seg * t;
inline seg * newseg(seg * =NULL);
seg * insert(seg * , int, int, int, int);
void query(seg * , int, int, int, int, int);

int main()
{
    int ans=0;

    n=getint();
    S=0; T=n+1; V=n+1;
    for (int i=1;i<=n;i++)
    {
        a[i]=getint(), b[i]=getint(), w[i]=getint(), l[i]=getint(), r[i]=getint(), p[i]=getint();
        ans+=b[i]+w[i];
        link(S, i, b[i]); link(i, T, w[i]);
        link(i, ++V, p[i]);
        query(t, 0, inf, l[i], r[i], V);
        t=insert(t, 0, inf, a[i], i);
    }

    ans-=isap();
    putint(ans);

    return 0;
}
inline int min(int x, int y)
{
    return x<y?x:y;
}
inline int getint()
{
    register int num=0;
    register char ch;
    do ch=getchar(); while (ch<'0' || ch>'9');
    do num=num*10+ch-'0', ch=getchar(); while (ch>='0' && ch<='9');
    return num;
}
inline void putint(int num)
{
    char stack[11];
    register int top=0;
    if (num==0) stack[top=1]='0';
    for ( ;num;num/=10) stack[++top]=num%10+'0';
    for ( ;top;top--) putchar(stack[top]);
    putchar('
');
}
inline edge * newedge(int point, int flow, edge * next)
{
    edge * ret=port_edge++;
    ret->point=point; ret->flow=flow; ret->next=next;
    return ret;
}
inline void link(int u, int v, int f)
{
    e[u]=newedge(v, f, e[u]); e[v]=newedge(u, 0, e[v]);
    e[u]->pair=e[v]; e[v]->pair=e[u];
}
inline bool bfs()
{
    static int q[sizeOfPoint];
    static int l, r;
    memset(h, 0xFF, sizeof(h)); h[T]=0;
    l=r=0;
    for (q[r++]=T;l<r;l++)
    {
        int u=q[l];
        ++gap[h[u]];
        for (edge * i=e[u];i;i=i->next) if (h[i->point]==-1)
        {
            h[i->point]=h[u]+1;
            q[r++]=i->point;
        }
    }
    return h[S]>-1;
}
inline int isap()
{
    static edge * t[sizeOfPoint], * p[sizeOfPoint];
    static int aug[sizeOfPoint];
    int flow=0, hmin=0;

    if (!bfs()) return 0;

    memcpy(t, e, sizeof(e)); memset(p, 0, sizeof(p));
    aug[S]=inf;
    for (int u=S;h[S]<V; )
    {
        if (u==T)
        {
            flow+=aug[T];
            for (edge * i=p[T];i;i=p[i->point])
                aug[i->point]-=aug[T], i->pair->flow-=aug[T], i->flow+=aug[T];
            for (edge * i=p[T];i;i=p[i->point]) if (aug[i->point])
            {
                u=i->point;
                break;
            }
        }

        edge *& i=t[u];
        for ( ;i && (!i->flow || h[i->point]+1!=h[u]);i=i->next);
        if (i)
        {
            aug[i->point]=min(aug[u], i->flow); p[i->point]=i->pair;
            u=i->point;
        }
        else
        {
            if (!--gap[h[u]]) break;
            hmin=V;
            for (edge * j=e[u];j;j=j->next) if (j->flow && h[j->point]+1<hmin)
            {
                hmin=h[j->point]+1;
                t[u]=j;
            }
            ++gap[h[u]=hmin];
            u=u==S?S:p[u]->point;
        }
    }

    return flow;
}
inline seg * newseg(seg * t)
{
    seg * newt=port_seg++;
    newt->p=++V; newt->l=t?t->l:NULL; newt->r=t?t->r:NULL;
    return newt;
}
seg * insert(seg * t, int l, int r, int p, int v)
{
    seg * newt=newseg(t);
    if (l==r)
    {
        if (t) link(newt->p, t->p, inf);
        link(newt->p, v, inf);
    }
    else
    {
        int m=(l+r)>>1;
        if (p<=m)
        {
            newt->l=insert(newt->l, l, m, p, v), link(newt->p, newt->l->p, inf);
            if (newt->r) link(newt->p, newt->r->p, inf);
        }
        else
        {
            newt->r=insert(newt->r, m+1, r, p, v), link(newt->p, newt->r->p, inf);
            if (newt->l) link(newt->p, newt->l->p, inf);
        }
    }

    return newt;
}
void query(seg * t, int l, int r, int ql, int qr, int v)
{
    if (!t) return ;
    if (l==ql && r==qr) link(v, t->p, inf);
    else
    {
        int m=(l+r)>>1;
        if (qr<=m) query(t->l, l, m, ql, qr, v);
        else if (ql>=m+1) query(t->r, m+1, r, ql, qr, v);
        else query(t->l, l, m, ql, m, v), query(t->r, m+1, r, m+1, qr, v);
    }
}

尝试着用了用 Data Display Debugger 觉得是很强大但是总觉得也很不顺手？

不过反正有了这个我是不想再去用 gdb 了……