BZOJ 4543: [POI2014]Hotel加强版 长链剖分

4543: [POI2014]Hotel加强版

Time Limit: 10 Sec  Memory Limit: 128 MB
Submit: 373  Solved: 205
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Description

同OJ3522
数据范围：n<=100000

Input

Output

Sample Input

7
1 2
5 7
2 5
2 3
5 6
4 5

Sample Output

5

懒懒懒

#include<cmath>#include<ctime>#include<cstdio>#include<cstdlib>#include<cstring>#include<iostream>#include<algorithm>#include<iomanip>#include<vector>#include<string>#include<bitset>#include<queue>#include<set>#include<map>using namespace std;typedef long long ll;inline int read(){int x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch<='9'&&ch>='0'){x=(x<<1)+(x<<3)+ch-'0';ch=getchar();}return x*f;}void print(ll x){if(x<0)putchar('-'),x=-x;if(x>=10)print(x/10);putchar(x%10+'0');}const int N=100100;int n,ecnt,last[N];struct EDGE{int to,nt;}e[N<<1];inline void add(int u,int v){e[++ecnt]=(EDGE){v,last[u]};last[u]=ecnt;}ll wa[N<<5];ll *f[N],*g[N],*p=wa;int d[N],fa[N],son[N],mx[N];void build(int u){mx[u]=u;for(int i=last[u];i;i=e[i].nt)if(e[i].to^fa[u]){fa[e[i].to]=u;build(e[i].to);if(d[e[i].to]>d[son[u]])mx[u]=mx[e[i].to],son[u]=e[i].to;}d[u]=son[u]==u?0:d[son[u]]+1;for(int i=last[u];i;i=e[i].nt){if(e[i].to==fa[u]||(e[i].to==son[u]&&u^1))continue;p+=d[e[i].to]+5;f[mx[e[i].to]]=p;p+=5;g[mx[e[i].to]]=p;p+=2*d[e[i].to]+5;}}ll ans;void dfs(int u){//cout<<u<<" "<<fa[u]<<endl;for(int i=last[u];i;i=e[i].nt)if(e[i].to^fa[u]){dfs(e[i].to);if(e[i].to==son[u])f[u]=f[e[i].to]-1,g[u]=g[e[i].to]+1;}ans+=g[u][0];f[u][0]=1;for(int i=last[u];i;i=e[i].nt){if(e[i].to==fa[u]||e[i].to==son[u])continue;ans+=g[u][1];for(int k=1;k<=d[e[i].to];++k){ans+=g[e[i].to][k]*f[u][k-1];ans+=f[e[i].to][k]*g[u][k+1];}for(int k=0;k<=d[e[i].to];++k){g[u][k-1]+=g[e[i].to][k];g[u][k+1]+=f[e[i].to][k]*f[u][k+1];f[u][k+1]+=f[e[i].to][k];}}}int main(){n=read();register int i,u,v;for(i=1;i<n;++i){u=read();v=read();add(u,v);add(v,u);}if(n==1){puts("0");return 0;}build(1);dfs(1);print(ans);puts("");return 0;}