bzoj4400: tjoi2012 桥

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#include <iostream> #include <cstdio> #include <cmath> #include <cstring> #include <cmath> #include <algorithm> #include <vector> #include <queue> #define N 100005 #define M 400005 #define INF 0x7FFFFFFF   using namespace std; inline int read(){     int ret=0;char ch=getchar();     while (ch<'0' || ch>'9') ch=getchar();     while ('0'<=ch && ch<='9'){         ret=ret*10-48+ch;         ch=getchar();     }     return ret; }   struct STnode{     int l,r;     int tag; };   int a[N]; struct SegmentTree{     STnode t[4*N];     void PushDown(int x){         if (t[x].l==t[x].r) return;         if (t[x].tag==INF) return;         t[x<<1].tag=min(t[x<<1].tag,t[x].tag);         t[x<<1^1].tag=min(t[x<<1^1].tag,t[x].tag);         t[x].tag=INF;     }     void build(int x,int l,int r){         t[x].l=l;t[x].r=r;t[x].tag=INF;         if (l==r) return;         int mid=(l+r)/2;         build(x<<1,l,mid);         build(x<<1^1,mid+1,r);     }     void modify(int x,int l,int r,int value){         PushDown(x);         if (l<=t[x].l&&t[x].r<=r){             t[x].tag=min(t[x].tag,value);             return;         }         int mid=(t[x].l+t[x].r)/2;         if (l<=mid) modify(x<<1,l,r,value);         if (r>mid) modify(x<<1^1,l,r,value);     }     int getans(int x){         if (t[x].l==t[x].r){a[t[x].l]=t[x].tag;return t[x].tag;}         PushDown(x);         return max(getans(x<<1),getans(x<<1^1));     } } st;     struct edge{     int adj,next,len;     int id;     edge(){}     edge(int _adj,int _next,int _len):adj(_adj),next(_next),len(_len){} } e[M]; int n,g[N],m; void AddEdge(int u,int v,int w){     e[++m]=edge(v,g[u],w);g[u]=m; }     struct HeapNode{     int pos,value;     HeapNode(){}     HeapNode(int _pos,int _value):pos(_pos),value(_value){} }; bool operator >(const HeapNode &x,const HeapNode &y){     return x.value>y.value; } priority_queue<HeapNode,vector<HeapNode> ,greater<HeapNode> > h;   int fa[N]; int mind[N]; bool flag[N]; int from[N]; void dijkstra(int _s){     memset(mind,127,sizeof(mind));     memset(flag,0,sizeof(flag));     h.push(HeapNode(_s,mind[_s]=0));     fa[_s]=from[_s]=0;     while (!h.empty()){         int u=h.top().pos;         h.pop();         flag[u]=1;         for (int i=g[u];i;i=e[i].next){             int v=e[i].adj;             if (mind[v]>mind[u]+e[i].len){                 mind[v]=mind[u]+e[i].len;                 h.push(HeapNode(v,mind[v]));                 fa[v]=u;from[v]=i;             }         }         while (!h.empty()&&flag[h.top().pos]) h.pop();     } }   int deep[N]; void dfs(int u){     for (int i=g[u];i;i=e[i].next){         int v=e[i].adj;         if (!deep[v]) deep[v]=deep[u];         dfs(v);     } }   void rebuild(){     memset(deep,0,sizeof(deep));     deep[n]=1;     for (int i=n;fa[i];i=fa[i]) deep[fa[i]]=deep[i]+1;     memset(g,0,sizeof(g));m=1;     for (int i=2;i<=n;++i) AddEdge(fa[i],i,0);     dfs(1); }     int u[M],v[M],w[M]; int dist[N];   int main(){     n=read();int m0=read();     memset(g,0,sizeof(g));m=1;     for (int i=1;i<=m0;++i){         u[i]=read();v[i]=read();w[i]=read();         AddEdge(u[i],v[i],w[i]);e[m].id=i;         AddEdge(v[i],u[i],w[i]);e[m].id=i;     }     dijkstra(n);     for (int i=1;i<=n;++i) dist[i]=mind[i];     dijkstra(1);     for (int i=2;i<=n;++i) w[e[from[i]].id]=0;     rebuild();     st.build(1,1,deep[1]-1);     for (int i=1;i<=m0;++i)if (w[i]){         if (deep[u[i]]>deep[v[i]]) swap(u[i],v[i]);         int x=deep[u[i]],y=deep[v[i]];         if (x==y) continue;         st.modify(1,x,y-1,dist[u[i]]+w[i]+mind[v[i]]);     }     int ans=st.getans(1),cnt=0;     for (int i=1;i<deep[1];++i) cnt+=(a[i]==ans);     printf("%d %d\n",ans,ans==mind[n]?m0:cnt);     return 0; }