【Codevs3306】水果姐逛水果街Ⅲ 树链剖分

改！了！好！多！天！

线段树尝试了下zkw，也算有所收获

注释有空再加

#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>#include<vector>using namespace std;#define pb push_back const int inf=1047483647;int n,m,fa[200010],top[200010],v[200010],w[200010],siz[200010],son[200010],f[1000010][4],ans,maxp,cntw,dep[200010],maxv,minv;vector<int> a[200010];void init(){for (maxp=1;maxp<=n+2;maxp<<=1);f[maxp][0]=-inf;f[maxp][1]=inf;f[maxp*2-1][0]=-inf;f[maxp*2-1][1]=inf;}void dfs1(int ro){int y;siz[ro]=1;son[ro]=0;for (int i=0;i<a[ro].size();i++) {y=a[ro][i];if (y==fa[ro]) continue;fa[y]=ro;dep[y]=dep[ro]+1;dfs1(y);siz[ro]+=siz[y];if (siz[y]>siz[son[ro]]) son[ro]=y;} return ;}void dfs2(int ro){int y;if (ro>1) w[ro]=++cntw;if (son[ro]) {top[son[ro]]=top[ro];dfs2(son[ro]);}for (int i=0;i<a[ro].size();i++){y=a[ro][i];if (y==son[ro]||y==fa[ro]) continue;top[y]=y;dfs2(y);}}void zkw_ins_single(int pos,int value){int tmp=maxp+pos;f[tmp][0]=value;f[tmp][1]=value;f[tmp][2]=f[tmp][3]=0;tmp>>=1;for (;tmp>=1;tmp>>=1){f[tmp][0]=max(f[tmp*2][0],f[tmp*2+1][0]);f[tmp][1]=min(f[tmp*2][1],f[tmp*2+1][1]);f[tmp][2]=max(f[tmp*2][0]-f[tmp*2+1][1],max(f[tmp*2][2],f[tmp*2+1][2]));f[tmp][3]=max(f[tmp*2+1][0]-f[tmp*2][1],max(f[tmp*2][3],f[tmp*2+1][3]));}}int zkw_query(int ty,int l,int r){l=maxp+l-1;r=maxp+r+1;int tmp,tmp1,tmp2;if (ty==0) tmp=inf;else tmp=-inf;tmp1=-inf;tmp2=inf;for (;r-l>1;l>>=1,r>>=1){if (~l&1) ans=max(ans,f[l+1][2+ty]);if (r&1) ans=max(ans,f[r-1][2+ty]);if (ty==0) {if (~l&1) {tmp=min(tmp,f[l+1][1]);ans=max(ans,tmp1-f[l+1][1]);tmp1=max(tmp1,f[l+1][0]);}if (r&1) {tmp=min(tmp,f[r-1][1]);ans=max(ans,f[r-1][0]-tmp2);tmp2=min(tmp2,f[r-1][1]);}}else {if (r&1) {tmp=max(tmp,f[r-1][0]);ans=max(ans,tmp1-f[r-1][1]);tmp1=max(tmp1,f[r-1][0]);}if (~l&1) {tmp=max(tmp,f[l+1][0]);ans=max(ans,f[l+1][0]-tmp2);tmp2=min(tmp2,f[l+1][1]);}}if (~l&1) {ans=max(ans,f[l+1][0]-minv);ans=max(ans,maxv-f[l+1][1]);}if (r&1){ans=max(ans,f[r-1][0]-minv);ans=max(ans,maxv-f[r-1][1]);}}ans=max(ans,tmp1-tmp2);return tmp;}void query(int x,int y){ans=0;maxv=-inf;minv=inf;int d=0;while (x!=y){if (top[x]==top[y]){if (dep[x]>dep[y]){swap(x,y);d^=1;}if (d==0) minv=min(minv,zkw_query(0,w[x]+1,w[y]));else maxv=max(maxv,zkw_query(1,w[x]+1,w[y]));y=x;break;}if (dep[top[x]]>dep[top[y]]){swap(x,y);d^=1;}if (top[y]==y){if (d==0) minv=min(minv,v[y]);else maxv=max(maxv,v[y]);ans=max(ans,max(maxv-v[y],v[y]-minv));y=fa[y];continue;}if (d==0) minv=min(minv,zkw_query(0,w[top[y]]+1,w[y]));else maxv=max(maxv,zkw_query(1,w[top[y]]+1,w[y]));y=top[y];}maxv=max(maxv,v[x]);minv=min(minv,v[x]);ans=max(ans,maxv-minv);}int main(){scanf("%d",&n);init();for (int i=1;i<=n;i++) scanf("%d",&v[i]);for (int i=1;i<=n;i++) v[i]=-v[i];int x,y,z;for (int i=1;i<n;i++) {scanf("%d%d",&x,&y);a[x].pb(y);a[y].pb(x);}dep[1]=1;dfs1(1);top[1]=1;dfs2(1);for (int i=2;i<=n;i++) if (w[i]) zkw_ins_single(w[i],v[i]);//for (int i=1;i<=n;i++) printf("%d %d %d %d %d\n",i,fa[i],top[i],w[i],v[i]);scanf("%d",&m);for (int i=1;i<=m;i++){scanf("%d%d%d",&x,&y,&z);if (x==0){v[y]=-z;if (w[y]) zkw_ins_single(w[y],v[y]);}else if (x==1){query(y,z);printf("%d\n",ans);}}}