SPOJ QTREE - Query on a tree(树链剖分)
来源:互联网 发布:21天阿里云推荐系统 编辑:程序博客网 时间:2024/06/06 02:44
You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1.
We will ask you to perfrom some instructions of the following form:
- CHANGE i ti : change the cost of the i-th edge to ti
or - QUERY a b : ask for the maximum edge cost on the path from node a to node b
Input
The first line of input contains an integer t, the number of test cases (t <= 20). t test cases follow.
For each test case:
- In the first line there is an integer N (N <= 10000),
- In the next N-1 lines, the i-th line describes the i-th edge: a line with three integers a b c denotes an edge between a, b of cost c (c <= 1000000),
- The next lines contain instructions "CHANGE i ti" or "QUERY a b",
- The end of each test case is signified by the string "DONE".
There is one blank line between successive tests.
Output
For each "QUERY" operation, write one integer representing its result.
Example
Input:131 2 12 3 2QUERY 1 2CHANGE 1 3QUERY 1 2DONEOutput:13
分析:入门题。细节还要看下。
#include<cstdio>#include<cstring>#include<algorithm>#include<vector>#include<string>#include<iostream>#include<queue>#include<cmath>#include<map>#include<stack>#include<set>using namespace std;#define REPF( i , a , b ) for ( int i = a ; i <= b ; ++ i )#define REP( i , n ) for ( int i = 0 ; i < n ; ++ i )#define CLEAR( a , x ) memset ( a , x , sizeof a )const int INF=0x3f3f3f3f;typedef long long LL;const int maxn=10010;struct node{ int to,next;}e[maxn*2];int head[maxn],tot,pos;int top[maxn],fa[maxn],deep[maxn],num[maxn],p[maxn],son[maxn],fp[maxn];int t,n;int op[maxn][3];void init(){ tot=0;pos=0; CLEAR(head,-1); CLEAR(son,-1);}void addedge(int u,int v){ e[tot].to=v;e[tot].next=head[u]; head[u]=tot++;}void dfs1(int u,int pre,int d){ deep[u]=d;fa[u]=pre; num[u]=1; for(int i=head[u];i!=-1;i=e[i].next) { int v=e[i].to; if(pre==v) continue; dfs1(v,u,d+1); num[u]+=num[v]; if(son[u]==-1||num[v]>num[son[u]]) son[u]=v; }}void dfs2(int u,int d){ top[u]=d; p[u]=pos++; fp[p[u]]=u; if(son[u]==-1) return ; dfs2(son[u],d); for(int i=head[u];i!=-1;i=e[i].next) { int v=e[i].to; if(son[u]!=v&&v!=fa[u]) dfs2(v,v); }}int sum[maxn<<2];void pushup(int rs){ sum[rs]=max(sum[rs<<1],sum[rs<<1|1]);}void update(int x,int c,int l,int r,int rs){ if(l==r) { sum[rs]=c; return ; } int mid=(l+r)>>1; if(x<=mid) update(x,c,l,mid,rs<<1); else update(x,c,mid+1,r,rs<<1|1); pushup(rs);}int query(int x,int y,int l,int r,int rs){ if(l>=x&&r<=y) return sum[rs]; int mid=(l+r)>>1; int res=0; if(x<=mid) res=max(res,query(x,y,l,mid,rs<<1)); if(y>mid) res=max(res,query(x,y,mid+1,r,rs<<1|1)); return res;}int Find(int u,int v){ int f1=top[u],f2=top[v]; int res=0; while(f1!=f2) { if(deep[f1]<deep[f2]) { swap(f1,f2); swap(u,v); } res=max(res,query(p[f1],p[u],1,pos,1)); u=fa[f1];f1=top[u]; } if(u==v) return res; if(deep[u]>deep[v]) swap(u,v); return max(res,query(p[son[u]],p[v],1,pos,1));}int main(){ int x,y,w; scanf("%d",&t); while(t--) { scanf("%d",&n); init(); for(int i=0;i<n-1;i++) { scanf("%d%d%d",&op[i][0],&op[i][1],&op[i][2]); addedge(op[i][0],op[i][1]); addedge(op[i][1],op[i][0]); } dfs1(1,0,0); dfs2(1,1); CLEAR(sum,0);//build(1,1,n); for(int i=0;i<n-1;i++) { if(deep[op[i][0]]>deep[op[i][1]]) swap(op[i][0],op[i][1]); update(p[op[i][1]],op[i][2],1,pos,1); } char str[10]; while(~scanf("%s",str)) { if(str[0]=='D') break; scanf("%d%d",&x,&y); if(str[0]=='Q') printf("%d\n",Find(x,y)); else update(p[op[x-1][1]],y,1,pos,1); } } return 0;}
0 0
- SPOJ QTREE(Query on a tree树链剖分)
- SPOJ QTREE Query on a tree --树链剖分
- [ SPOJ - QTREE]Query on a tree && 树链剖分
- SPOJ QTREE Query on a tree 树链剖分
- SPOJ QTREE Query on a tree 树链剖分
- 【树链剖分】[SPOJ-QTREE]Query on a tree
- SPOJ QTREE - Query on a tree 【树链剖分】
- SPOJ QTREE- Query on a tree (树链剖分)
- [spoj QTREE Query on a tree]树链剖分
- SPOJ QTREE Query on a tree(树链剖分)
- SPOJ 375 QTREE系列-Query on a tree (树链剖分)
- SPOJ QTREE Query on a tree (树链剖分)
- SPOJ QTREE - Query on a tree(树链剖分)
- SPOJ 题目 375 QTREE - Query on a tree(树链剖分)
- [SPOJ QTREE] Query on a tree (树链剖分)
- SPOJ QTREE Query on a tree(树链剖分+线段树)
- Spoj Query on a tree SPOJ - QTREE(树链剖分+线段树)
- SPOJ QTREE 375. Query on a tree
- 成员变量、类变量、局部变量的区别
- 异常
- 找出第二个文本抄袭第一个文本的所有位置和长度 后缀数组 UVA 10526 - Intellectual Property
- 数据库的事物隔离级别通俗理解
- 剑指offer—从上往下打印二叉树
- SPOJ QTREE - Query on a tree(树链剖分)
- HDOJ 5494 Card Game(水)
- 【bzoj3034】Heaven Cow与God Bull
- 项目问题思考之策略模式
- 测试1003
- ZOJ3822-Domination 概率DP
- Hadoop学习笔记(六)启动Shell分析
- 动态计算UITableViewCell高度详解
- DirectX11 板条箱示例Demo