CF1230 E. Kamil and Making a Stream gcd+暴力
比赛的时候TLE,第二天发现合并方向合并错了~
改了一下顺序就切了~
又掉分了,好难过QAQ......
Code:
#include <bits/stdc++.h> #define N 100005 #define mod 1000000007 #define ll long long #define setIO(s) freopen(s".in","r",stdin) using namespace std; struct Node { ll gc,tmp; Node(ll gc=0,ll tmp=0):gc(gc),tmp(tmp){} }; bool cmp(Node a,Node b) { return a.gc < b.gc; } vector<Node>G[N]; vector<Node>A; int n,edges; ll val[N], ans=0; int hd[N],to[N<<1],nex[N<<1]; void add(int u,int v) { nex[++edges]=hd[u],hd[u]=edges,to[edges]=v; } void dfs(int u,int ff) { if(ff!=0) { A.clear(); for(int j=0;j<G[ff].size();++j) A.push_back(G[ff][j]); for(int i=0;i<A.size();++i) A[i].gc=__gcd(A[i].gc, val[u]); } A.push_back(Node(val[u], 1)); sort(A.begin(), A.end(), cmp); int i,j; for(i=0;i<A.size();i=j) { for(j=i;j<A.size() && A[j].gc==A[i].gc;) { ++j; } ll pp=0; for(int k=i;k<j;++k) { pp+=A[k].tmp; } G[u].push_back(Node(A[i].gc, pp)); } sort(G[u].begin(), G[u].end(), cmp); for(i=0;i<G[u].size();++i) ans=(ans+G[u][i].gc*G[u][i].tmp%mod)%mod; for(int i=hd[u];i;i=nex[i]) { int v=to[i]; if(v==ff) continue; dfs(v, u); } } int main() { int i,j; // setIO("input"); scanf("%d",&n); for(i=1;i<=n;++i) scanf("%lld",&val[i]); for(i=1;i<n;++i) { int a,b; scanf("%d%d",&a,&b), add(a,b),add(b,a); } dfs(1,0); printf("%lld\n",ans); return 0; }