hdu5029 Relief grain
树剖+线段树
将区间修改转化为单点修改，因为如果按DFS序进行修改，那么一定会对DFS序更大的点造成影响
1 #include<iostream> 2 #include<vector> 3 #include<cstdio> 4 #include<cstdlib> 5 #include<string> 6 #include<cstring> 7 #include<cmath> 8 #include<algorithm> 9 #define re(i,l,r) for(int i=(l);i<=(r);i++) 10 using namespace std; 11 template <typename Q> 12 void inin(Q &ret) 13 { 14 ret=0;int f=0;char ch=getchar(); 15 while(ch<'0'||ch>'9'){if(ch=='0')f=1;ch=getchar();} 16 while(ch>='0'&&ch<='9')ret=(ret<<3)+(ret<<1)+ch-'0',ch=getchar(); 17 ret=f?-ret:ret; 18 } 19 const int xxx=100010; 20 int head[xxx],Next[xxx<<1],zhi[xxx<<1],n,m,dui[xxx],ans[xxx]; 21 int top[xxx],shen[xxx],fa[xxx],ed,dfn[xxx],son[xxx]; 22 vector<int>in[xxx],out[xxx]; 23 void add(int a,int b) 24 { 25 Next[++ed]=head[a],head[a]=ed,zhi[ed]=b; 26 Next[++ed]=head[b],head[b]=ed,zhi[ed]=a; 27 } 28 int dfs(int x) 29 { 30 int ret=1,Max=0,temp; 31 for(int i=head[x];i;i=Next[i])if(zhi[i]!=fa[x]) 32 { 33 fa[zhi[i]]=x,shen[zhi[i]]=shen[x]+1; 34 temp=dfs(zhi[i]); 35 ret+=temp; 36 if(Max<temp)Max=temp,son[x]=zhi[i]; 37 } 38 return ret; 39 } 40 int tot; 41 void dfs(int x,int t) 42 { 43 if(!x)return ; 44 top[x]=t;dfn[x]=++tot,dui[tot]=x; 45 dfs(son[x],t); 46 for(int i=head[x];i;i=Next[i])if(zhi[i]!=fa[x]&&zhi[i]!=son[x]) 47 dfs(zhi[i],zhi[i]); 48 } 49 void change(int x,int y,int z) 50 { 51 while(top[x]!=top[y]) 52 if(shen[top[x]]>shen[top[y]]) 53 in[dfn[top[x]]].push_back(z), 54 out[dfn[x]+1].push_back(z), 55 x=fa[top[x]]; 56 else in[dfn[top[y]]].push_back(z), 57 out[dfn[y]+1].push_back(z), 58 y=fa[top[y]]; 59 if(shen[x]>shen[y])swap(x,y); 60 in[dfn[x]].push_back(z),out[dfn[y]+1].push_back(z); 61 } 62 struct tree 63 { 64 int l,r,Max,o; 65 }t[400040]; 66 void UP(int k) 67 { 68 int p1=k<<1,p2=p1|1; 69 if(t[p1].Max>=t[p2].Max)t[k].Max=t[p1].Max,t[k].o=t[p1].o; 70 else t[k].Max=t[p2].Max,t[k].o=t[p2].o; 71 } 72 void build(int k,int l,int r) 73 { 74 t[k].l=l,t[k].r=r;t[k].Max=0,t[k].o=l; 75 if(l==r)return ; 76 int mid=(l+r)>>1,p1=k<<1,p2=p1|1; 77 build(p1,l,mid),build(p2,mid+1,r); 78 UP(k); 79 } 80 void update(int k,int se,int x) 81 { 82 if(t[k].l==t[k].r){t[k].Max+=x;return ;} 83 int mid=(t[k].l+t[k].r)>>1,p1=k<<1,p2=p1|1; 84 if(se<=mid)update(p1,se,x); 85 else update(p2,se,x); 86 UP(k); 87 } 88 int main() 89 { 90 while(scanf("%d%d",&n,&m),n) 91 { 92 tot=0; 93 ed=0;memset(head,0,sizeof head); 94 memset(son,0,sizeof son); 95 re(i,2,n) 96 { 97 int a,b;inin(a),inin(b); 98 add(a,b); 99 } 100 dfs(1); 101 dfs(1,1);int Max=0; 102 // re(i,1,n) 103 // { 104 // printf("%d : ",i); 105 // cout<<"in:";re(j,0,(int)in[i].size()-1)printf("%d ",in[i][j]);cout<<"\n"; 106 // cout<<"out:";re(j,0,(int)out[i].size()-1)printf("%d ",out[i][j]);cout<<"\n"; 107 // } 108 re(i,1,m) 109 { 110 int x,y,z; 111 inin(x),inin(y),inin(z); 112 change(x,y,z),Max=max(Max,z); 113 } 114 build(1,1,Max+1); 115 re(i,1,n) 116 { 117 re(j,0,(int)in[i].size()-1) 118 update(1,in[i][j],1); 119 re(j,0,(int)out[i].size()-1) 120 update(1,out[i][j],-1); 121 ans[dui[i]]=t[1].Max?t[1].o:0; 122 } 123 re(i,1,n)printf("%d\n",ans[i]); 124 re(i,1,n+1)in[i].clear(),out[i].clear(); 125 } 126 return 0; 127 }
