因为一棵树的子树一定在dfs序上是连续的
所以直接修改就行了
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | #include<cstdio>#include<algorithm>using namespace std;struct Edge{int b,next;}e[1000005];struct SegTree{int l,r;long long tag,sum;}tree[1000005];int n,q,en,cnt,top[400005],id[400005],pre[400005],dep[400005],son[400005],h[400005],siz[400005],fa[400005];void AddEdge(int sa,int sb){e[++en].b=sb;e[en].next=h[sa];h[sa]=en;}void Pushdown(int root){if(tree[root].tag){ tree[root*2].tag+=tree[root].tag; tree[root*2].sum+=tree[root].tag*(tree[root*2].r-tree[root*2].l+1); tree[root*2+1].tag+=tree[root].tag; tree[root*2+1].sum+=tree[root].tag*(tree[root*2+1].r-tree[root*2+1].l+1); tree[root].tag=0;}}void Pushup(int root){tree[root].sum=tree[root*2].sum+tree[root*2+1].sum;}void Build(int root,int l,int r){tree[root].l=l;tree[root].r=r;if(l==r){ tree[root].sum=0; return;}int mid=(l+r)/2;Build(root*2,l,mid);Build(root*2+1,mid+1,r);tree[root].sum=tree[root*2].sum+tree[root*2+1].sum;}void Add(int root,int l,int r,long long v){if(tree[root].l>=l && tree[root].r<=r){ tree[root].tag+=v; tree[root].sum+=v*(tree[root].r-tree[root].l+1); return;}Pushdown(root);int mid=tree[root].l+tree[root].r>>1;if(l<=mid)Add(root*2,l,r,v);if(r>mid)Add(root*2+1,l,r,v);Pushup(root);}long long Sum(int root,int l,int r){if(tree[root].l>=l && tree[root].r<=r){ return tree[root].sum;}Pushdown(root);int mid=tree[root].l+tree[root].r>>1;long long ans=0;if(l<=mid)ans+=Sum(root*2,l,r);if(r>mid)ans+=Sum(root*2+1,l,r);return ans;}void dfs1(int u,int father,int deep){fa[u]=father;dep[u]=deep;siz[u]=1;son[u]=0;for(int i=h[u];i;i=e[i].next){ int v=e[i].b; if(v==father)continue; dfs1(v,u,deep+1); siz[u]+=siz[v]; if(siz[v]>siz[son[u]]){ son[u]=v; }}} void dfs2(int u,int ux){top[u]=ux;id[u]=++cnt;pre[cnt]=u;if(son[u])dfs2(son[u],ux);else return;for(int i=h[u];i;i=e[i].next){ int v=e[i].b; if(v!=son[u] && v!=fa[u]){dfs2(v,v);}}}void AddLine(int u,int v,long long val){int f1=top[u],f2=top[v];while(f1!=f2){ if(dep[f1]<dep[f2]){swap(u,v);swap(f1,f2);} Add(1,id[f1],id[u],val); u=fa[f1]; f1=top[u];}if(dep[u]>dep[v])swap(u,v);//printf("%d %d\n",id[u],id[v]);Add(1,id[u],id[v],val);}int main(){freopen("2836.in","r",stdin);freopen("2836.out","w",stdout);scanf("%d",&n);for(int i=1;i<n;i++){ int u,v; scanf("%d %d",&u,&v); AddEdge(u+1,v+1); AddEdge(v+1,u+1);}Build(1,1,n);dfs1(1,0,1);dfs2(1,1);scanf("%d",&q);while(q--){ int u,v; long long val; char s[3]; scanf("%s",s); if(s[0]=='A'){ scanf("%d %d %lld",&u,&v,&val); AddLine(u+1,v+1,val); } if(s[0]=='Q'){ scanf("%d",&u); //printf("IS:%d %d %d\n",id[u+1],siz[u+1],u+1); printf("%lld\n",Sum(1,id[u+1],id[u+1]+siz[u+1]-1)); }}return 0;} |
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