bzoj2157: 旅游

来源：互联网发布：黑页源码怎么用编辑：程序博客网时间：2024/04/27 21:22

树链剖分。

把边权转成深度大的点权，支持单点赋值，路径取反，路径求和，路径最值，用线段树即可完成。

因为第一种操作是对边的编号修改，一开始没注意WA了。。

#include<iostream>#include<cstdio>#define N 100000#define inf 1000000000using namespace std;int n,m,x,y,z,w[N],L[N];int first[N],to[N],v[N],next[N],l;int dep[N],Bson[N],size[N],fa[N],top[N],order[N],cnt;char s[100];struct node{int MAX,MIN,SUM,OPP;}a[N<<3];node operator+(node a,node b){return (node){max(a.MAX,b.MAX),min(a.MIN,b.MIN),a.SUM+b.SUM,0};}void down(int k){a[k]=(node){-a[k].MIN,-a[k].MAX,-a[k].SUM,0};a[k<<1].OPP^=1;a[k<<1|1].OPP^=1;}void link(int x,int y,int z){to[++l]=y;v[l]=z;next[l]=first[x];first[x]=l;to[++l]=x;v[l]=z;next[l]=first[y];first[y]=l;}void dfs(int x){dep[x]=dep[fa[x]]+1;size[x]=1;for (int i=first[x];i;i=next[i])if (to[i]!=fa[x]){w[to[i]]=v[i];fa[to[i]]=x;L[i]=L[((i+1)|1)-1]=to[i];dfs(to[i]);size[x]+=size[to[i]];if (size[to[i]]>size[Bson[x]]) Bson[x]=to[i];}}void dfs(int x,int y){top[x]=y;order[x]=++cnt;if (Bson[x]) dfs(Bson[x],y);for (int i=first[x];i;i=next[i])if (to[i]!=fa[x]){if (to[i]!=Bson[x]) dfs(to[i],to[i]);}}void mdy(int l,int r,int k,int x,int y){if (a[k].OPP) down(k);if (l==r){a[k]=(node){y,y,y,0};return;}int mid=(l+r)>>1;if (x<=mid) mdy(l,mid,k<<1,x,y);else mdy(mid+1,r,k<<1|1,x,y); if (a[k<<1].OPP) down(k<<1);if (a[k<<1|1].OPP) down(k<<1|1);a[k]=a[k<<1]+a[k<<1|1];}void opp(int l,int r,int k,int x,int y){if (a[k].OPP) down(k);if (x<=l&&r<=y){down(k);return;}int mid=(l+r)>>1;if (x<=mid) opp(l,mid,k<<1,x,y);if (y>mid) opp(mid+1,r,k<<1|1,x,y);if (a[k<<1].OPP) down(k<<1);if (a[k<<1|1].OPP) down(k<<1|1);a[k]=a[k<<1]+a[k<<1|1];}node qry(int l,int r,int k,int x,int y){if (a[k].OPP) down(k);if (a[k<<1].OPP) down(k<<1);if (a[k<<1|1].OPP) down(k<<1|1);if (x<=l&&r<=y) return a[k];int mid=(l+r)>>1;node Ans=(node){-inf,inf,0,0};if (x<=mid) Ans=Ans+qry(l,mid,k<<1,x,y);if (y>mid) Ans=Ans+qry(mid+1,r,k<<1|1,x,y);return Ans;}void make(char s[],int x,int y){node Ans=(node){-inf,inf,0,0};for (;top[x]!=top[y];x=fa[top[x]]){if (dep[top[x]]<dep[top[y]]) swap(x,y);if (s[0]=='N') opp(1,n,1,order[top[x]],order[x]);else Ans=Ans+qry(1,n,1,order[top[x]],order[x]);}if (dep[x]>dep[y]) swap(x,y);if (s[0]=='N') opp(1,n,1,order[x]+1,order[y]);else Ans=Ans+qry(1,n,1,order[x]+1,order[y]);if (s[0]=='S') printf("%d\n",Ans.SUM);else if (s[1]=='A') printf("%d\n",Ans.MAX);else if (s[1]=='I') printf("%d\n",Ans.MIN);}int main(){scanf("%d",&n);for (int i=1;i<n;i++)scanf("%d%d%d",&x,&y,&z),link(x+1,y+1,z);dfs(1);dfs(1,1);for (int i=1;i<=n*4;i++)a[i]=(node){-inf,inf,0,0};for (int i=2;i<=n;i++)mdy(1,n,1,order[i],w[i]);scanf("%d",&m);for (int i=1;i<=m;i++){scanf("%s%d%d",s,&x,&y);if (s[0]=='C') mdy(1,n,1,order[L[x<<1]],y); else make(s,x+1,y+1);}return 0;}

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