Submission #468973

#	Time	Username	Problem	Language	Result	Execution time	Memory
468973		wdjpng	Chase (CEOI17_chase)	C++17	70 / 100	2357 ms	94788 KiB

chase

#include <bits/stdc++.h>

#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")

#define int long long
#define rep(i,n) for(int i = 0; i < n; i++)

using namespace std;

int n,v;
vector<int>p;
vector<vector<int>>mem;
vector<vector<int>>E;

int dfs(int pos, int bc, int parent)
{
    if(mem[pos][bc]!=-1) return mem[pos][bc];
    if(bc==0) return 0;
    
    int sum = 0;
    for(int w : E[pos])
    {
        if(w==parent) continue;
        sum+=p[w];
    }

    int maxx = 0;
    for(int w : E[pos])
    {
        if(w==parent) continue;
        maxx=max(maxx, dfs(w, bc, pos));
        maxx=max(maxx, dfs(w, bc-1, pos) + sum);
    }

    return mem[pos][bc] = maxx;
}

int bruteforce()
{
    int maxx=0;
    rep(i, n) 
    {
        mem.assign(n+1, vector<int>(v+1, -1));
        maxx=max(maxx, dfs(i+1, v, -1));
    }
    return maxx;
}

signed main()
{
    cin>>n>>v;
    p.resize(n+1);
    rep(i, n) cin>>p[i+1];

    E.resize(n+1);
    mem.assign(n+1, vector<int>(v+1, -1));

    rep(i,n-1)
    {
        int a,b;
        cin>>a>>b;
        E[a].push_back(b);
        E[b].push_back(a);
    }
    int maxx = dfs(1, v, -1);
    if(n<=1000) maxx = bruteforce();
    cout<<maxx<<"\n";
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 0 / 30