一道简单树剖，把边权变为点权，随便写写就好了
1 #include<iostream> 2 #include<cstdio> 3 #include<string> 4 #include<cstring> 5 #include<cmath> 6 #include<algorithm> 7 #include<queue> 8 #include<stack> 9 #include<set> 10 #include<bitset> 11 #include<vector> 12 #include<cstdlib> 13 #define QAQ int 14 #define TAT long long 15 #define OwO bool 16 #define ORZ double 17 #define Ug unsigned 18 #define F(i,j,n) for(QAQ i=j;i<=n;++i) 19 #define E(i,j,n) for(QAQ i=j;i>=n;--i) 20 #define MES(i,j) memset(i,j,sizeof(i)) 21 #define MEC(i,j) memcpy(i,j,sizeof(j)) 22 #define mid (l+r>>1) 23 #define ls (o<<1) 24 #define rs (o<<1|1) 25 #define LS l,mid,ls 26 #define RS mid+1,r,rs 27 28 using namespace std; 29 const QAQ N=100005; 30 31 QAQ n; 32 struct Link{ 33 QAQ to,last,val; 34 }a[N<<1]; 35 QAQ head[N],js; 36 QAQ id[N],key[N]; 37 QAQ fa[N],son[N],size[N]; 38 QAQ top[N],val[N],deep[N]; 39 struct Seg{ 40 QAQ Max,ladd,lset; 41 OwO flag; 42 }tree[N<<2]; 43 char s[10]; 44 45 void add(QAQ x,QAQ y,QAQ z){ 46 a[++js].to=y;a[js].val=z; 47 a[js].last=head[x];head[x]=js; 48 } 49 50 void dfs1(QAQ x,QAQ f){ 51 fa[x]=f;size[x]=1; 52 for(QAQ i=head[x];i;i=a[i].last)if(a[i].to!=f){ 53 deep[a[i].to]=deep[x]+1; 54 dfs1(a[i].to,x); 55 val[a[i].to]=a[i].val; 56 if(!son[x]||size[son[x]]<size[a[i].to]) son[x]=a[i].to; 57 size[x]+=size[a[i].to]; 58 } 59 } 60 61 void dfs2(QAQ x,QAQ t){ 62 top[x]=t;id[x]=++js;key[js]=val[x]; 63 if(!son[x]) return ; 64 dfs2(son[x],t); 65 for(QAQ i=head[x];i;i=a[i].last) if(a[i].to!=fa[x]&&a[i].to!=son[x]) dfs2(a[i].to,a[i].to); 66 } 67 68 namespace Tree{ 69 void push_up(QAQ o){ 70 tree[o].Max=max(tree[ls].Max,tree[rs].Max); 71 } 72 73 void push_down(QAQ o){ 74 if(tree[o].flag){ 75 tree[ls].ladd=tree[rs].ladd=0; 76 tree[ls].flag=tree[rs].flag=1; 77 tree[ls].Max=tree[o].lset; 78 tree[rs].Max=tree[o].lset; 79 tree[ls].lset=tree[o].lset; 80 tree[rs].lset=tree[o].lset; 81 tree[o].lset=0;tree[o].ladd=0; 82 tree[o].flag=0; 83 } 84 if(tree[o].ladd){ 85 tree[ls].ladd+=tree[o].ladd; 86 tree[ls].lset+=tree[o].ladd; 87 tree[ls].Max+=tree[o].ladd; 88 tree[rs].ladd+=tree[o].ladd; 89 tree[rs].lset+=tree[o].ladd; 90 tree[rs].Max+=tree[o].ladd; 91 tree[o].ladd=0; 92 } 93 } 94 95 void build(QAQ l,QAQ r,QAQ o){ 96 if(l==r){ 97 tree[o].Max=key[l]; 98 return ; 99 } 100 build(LS);build(RS); 101 push_up(o); 102 } 103 104 void change(QAQ l,QAQ r,QAQ o,QAQ x,QAQ y,QAQ z){ 105 if(l>=x&&r<=y){ 106 tree[o].Max=z; 107 tree[o].ladd=0; 108 tree[o].lset=z; 109 tree[o].flag=1; 110 return ; 111 } 112 push_down(o); 113 if(x<=mid) change(LS,x,y,z); 114 if(y>mid) change(RS,x,y,z); 115 push_up(o); 116 } 117 118 void add(QAQ l,QAQ r,QAQ o,QAQ x,QAQ y,QAQ z){ 119 if(l>=x&&r<=y){ 120 tree[o].Max+=z; 121 tree[o].ladd+=z; 122 tree[o].lset+=z; 123 return ; 124 } 125 push_down(o); 126 if(x<=mid) add(LS,x,y,z); 127 if(y>mid) add(RS,x,y,z); 128 push_up(o); 129 } 130 131 QAQ query(QAQ l,QAQ r,QAQ o,QAQ x,QAQ y){ 132 if(l>=x&&r<=y) return tree[o].Max; 133 push_down(o); 134 QAQ ans=0; 135 if(x<=mid) ans=max(ans,query(LS,x,y)); 136 if(y>mid) ans=max(ans,query(RS,x,y)); 137 return ans; 138 } 139 } 140 141 void change(QAQ x,QAQ y,QAQ z){ 142 while(top[x]!=top[y]){ 143 if(deep[top[x]]<deep[top[y]]) swap(x,y); 144 Tree::change(1,n,1,id[top[x]],id[x],z); 145 x=fa[top[x]]; 146 } 147 if(x==y) return ; 148 if(deep[x]>deep[y]) swap(x,y); 149 Tree::change(1,n,1,id[x]+1,id[y],z); 150 } 151 152 void Add(QAQ x,QAQ y,QAQ z){ 153 while(top[x]!=top[y]){ 154 if(deep[top[x]]<deep[top[y]]) swap(x,y); 155 Tree::add(1,n,1,id[top[x]],id[x],z); 156 x=fa[top[x]]; 157 } 158 if(x==y) return ; 159 if(deep[x]>deep[y]) swap(x,y); 160 Tree::add(1,n,1,id[x]+1,id[y],z); 161 } 162 163 QAQ query(QAQ x,QAQ y){ 164 QAQ ans=0; 165 while(top[x]!=top[y]){ 166 if(deep[top[x]]<deep[top[y]]) swap(x,y); 167 ans=max(ans,Tree::query(1,n,1,id[top[x]],id[x])); 168 x=fa[top[x]]; 169 } 170 if(x==y) return ans; 171 if(deep[x]>deep[y]) swap(x,y); 172 ans=max(ans,Tree::query(1,n,1,id[x]+1,id[y])); 173 return ans; 174 } 175 176 QAQ main(){ 177 scanf("%d",&n); 178 F(i,1,n-1){ 179 QAQ u,v,w; 180 scanf("%d%d%d",&u,&v,&w); 181 add(u,v,w);add(v,u,w); 182 } 183 deep[1]=1;js=0; 184 dfs1(1,0); 185 dfs2(1,0); 186 Tree::build(1,n,1); 187 while(scanf("%s",s),s[0]!='S'){ 188 if(s[1]=='h'){ 189 QAQ k,w; 190 scanf("%d%d",&k,&w); 191 if(deep[a[k*2].to]>deep[a[k*2-1].to]) Tree::change(1,n,1,id[a[k*2].to],id[a[k*2].to],w); 192 else Tree::change(1,n,1,id[a[k*2-1].to],id[a[k*2-1].to],w); 193 } 194 else if(s[1]=='o'){ 195 QAQ x,y,z; 196 scanf("%d%d%d",&x,&y,&z); 197 change(x,y,z); 198 } 199 else if(s[1]=='d'){ 200 QAQ x,y,z; 201 scanf("%d%d%d",&x,&y,&z); 202 Add(x,y,z); 203 } 204 else { 205 QAQ x,y; 206 scanf("%d%d",&x,&y); 207 printf("%d ",query(x,y)); 208 } 209 } 210 return 0; 211 }