Submission #1147103

#	Time	Username	Problem	Language	Result	Execution time	Memory
1147103		Luvidi	Roadside Advertisements (NOI17_roadsideadverts)	C++20	100 / 100	48 ms	23368 KiB

roadsideadverts

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define fs first
#define sc second
#define pb push_back

const int maxn=5e4;
vector<pii> adj[maxn];
int idx[maxn],d[maxn],t,dp[maxn];
pii sp[2*maxn][20];

void dfs(int v,int p){
    idx[v]=t;
    sp[t++][0]={d[v],v};
    for(auto[u,w]:adj[v])if(u!=p){
        d[u]=d[v]+1;
        dp[u]=dp[v]+w;
        dfs(u,v);
        sp[t++][0]={d[v],v};
    }
}

int lca(int u,int v){
    int x=idx[u],y=idx[v];
    if(x>y)swap(x,y);
    int z=31-__builtin_clz(y-x+1);
    return min(sp[x][z],sp[y-(1<<z)+1][z]).sc;
}

int dist(int u,int v){
    return dp[u]+dp[v]-2*dp[lca(u,v)];
}

void solve() {
    int n;
    cin>>n;
    for(int i=0;i<n-1;i++){
        int u,v,w;
        cin>>u>>v>>w;
        adj[u].pb({v,w});
        adj[v].pb({u,w});
    }
    dfs(0,0);
    for(int i=1;i<20;i++){
        for(int j=0;j+(1<<i)<=t;j++){
            sp[j][i]=min(sp[j][i-1],sp[j+(1<<i-1)][i-1]);
        }
    }
    int q;
    cin>>q;
    while(q--){
        int a[5];
        for(int i=0;i<5;i++)cin>>a[i];
        sort(a,a+5,[&](int x,int y){return d[x]<d[y];});
        int r=lca(a[0],lca(a[1],lca(a[2],lca(a[3],a[4]))));
        int ans=0;
        for(int i=0;i<5;i++){
            int d=dp[lca(a[i],r)];
            for(int j=0;j<i;j++)d=max(d,dp[lca(a[i],a[j])]);
            ans+=dp[a[i]]-d;
        }
        cout<<ans<<'\n';
    }
}

int main() {
    #ifdef FPO
        freopen("in","r",stdin);
        freopen("out","w",stdout);
    #endif
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    solve();
}

• Subtask 1: 7 / 7
• Subtask 2: 23 / 23
• Subtask 3: 40 / 40
• Subtask 4: 30 / 30