线段树优化连边（cf 786B）

转载别人的看一看，记录一下。

http://blog.csdn.net/jinglinxiao/article/details/65638659




我的代码：

#include<bits/stdc++.h>
#define mid ((l+r)>>1)
#define ls (now<<1)
#define rs (ls|1)
using namespace std;
typedef long long ll;
const int maxn = 1e6+10;
const ll inf = LONG_LONG_MAX>>2;

struct Edge
{
int from,to;
int dist;
};

struct HeapNode
{
ll d;
int u;
bool operator < (const HeapNode& rhs) const
{
return d>rhs.d;
}
};

struct Dijkstra
{
int n,m;
vector<Edge>edges;
vector<int>G[maxn];
bool done[maxn];
ll d[maxn];
int p[maxn];
void init(int n)
{
this->n=n;
edges.clear();
for(int i=0;i<=n;i++) G[i].clear();
}
void Add_Edge(int from,int to,int dist)
{
edges.push_back((Edge){from,to,dist});
G[from].push_back(edges.size()-1);
}
void dijkstra(int s)
{
memset(done,0,sizeof(done));
for(int i=0;i<=n;i++) d[i]=inf;
d[s]=0;
priority_queue<HeapNode>q;
q.push((HeapNode){0,s});
while(!q.empty())
{
HeapNode now=q.top();
q.pop();
int u=now.u;
if(done[u]) continue;
done[u]=1;
for(int i=0;i<(int)G[u].size();i++)
{
Edge& e=edges[G[u][i]];
if(d[e.to]>d[e.from]+e.dist)
{
d[e.to]=d[e.from]+e.dist;
p[e.to]=G[u][i];
q.push((HeapNode){d[e.to],e.to});
}
}
}
}
}DIJ;

int n,q,s;
int id2[maxn];
int id3[maxn];

void build2(int l,int r,int now)
{
id2[now]=++n;
for(int i=l;i<=r;i++) DIJ.Add_Edge(id2[now],i,0);
if(l==r) return;
build2(l,mid,ls);
build2(mid+1,r,rs);
}

void build3(int l,int r,int now)
{
id3[now]=++n;
for(int i=l;i<=r;i++) DIJ.Add_Edge(i,id3[now],0);
if(l==r) return;
build3(l,mid,ls);
build3(mid+1,r,rs);
}

void add2(int l,int r,int now,int ql,int qr,int pos,int val)
{
if(l>qr||r<ql) return;
if(ql<=l&&r<=qr) {DIJ.Add_Edge(pos,id2[now],val);return;}
add2(l,mid,ls,ql,qr,pos,val);
add2(mid+1,r,rs,ql,qr,pos,val);
}

void add3(int l,int r,int now,int ql,int qr,int pos,int val)
{
if(l>qr||r<ql) return;
if(ql<=l&&r<=qr) {DIJ.Add_Edge(id3[now],pos,val);return;}
add3(l,mid,ls,ql,qr,pos,val);
add3(mid+1,r,rs,ql,qr,pos,val);
}

int main()
{
scanf("%d %d %d",&n,&q,&s);
int N=n;
DIJ.init(10*n);
build2(1,N,1);
build3(1,N,1);
int op,u,v,l,r,w;
while(q--)
{
scanf("%d",&op);
if(op==1)
{
scanf("%d %d %d",&u,&v,&w);
DIJ.Add_Edge(u,v,w);
}
else
{
scanf("%d %d %d %d",&v,&l,&r,&w);
if(op==2) add2(1,N,1,l,r,v,w);
else add3(1,N,1,l,r,v,w);
}
}
DIJ.dijkstra(s);
for(int i=1;i<=N;i++) printf("%lld%c",DIJ.d[i]==inf?-1:DIJ.d[i],i==N?'\n':' ');
return 0;
}