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Submission #469097

# Submission time Handle Problem Language Result Execution time Memory
469097 2021-08-30T17:23:30 Z wdjpng Chase (CEOI17_chase) C++17
0 / 100
 4000 ms 510196 KB 
#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<signed>>E;
vector<vector<signed>>takei;
vector<vector<signed>>notakei;
vector<vector<int>>takemaxx;
vector<vector<int>>takealtmaxx;
vector<vector<int>>notakealtmaxx;
vector<vector<int>>notakemaxx;
vector<signed>totsum(1e5+1);

int dfs(int pos, int bc, int parent)
{
    if(mem[pos][bc]!=-1) return mem[pos][bc];
    if(bc==0) return 0;
    
    int sum = totsum[pos];
    if(parent!=-1) sum-=p[parent];

    int maxx = 0;
    takemaxx[pos][bc]=0;
    takei[pos][bc] = -1;
    notakemaxx[pos][bc]=0;
    notakei[pos][bc] = -1;

    int t, nt;
    for(int w : E[pos])
    {
        if(w==parent) continue;
        nt = dfs(w, bc, pos);
        t = dfs(w, bc-1, pos) + sum;

        if(nt>notakemaxx[pos][bc])
        {
            notakei[pos][bc] = w;
            notakemaxx[pos][bc] = nt;
        }

        if(t>takemaxx[pos][bc])
        {
            takei[pos][bc] = w;
            takemaxx[pos][bc] = t;
        }

        maxx=max(maxx, nt);
        maxx=max(maxx, t);
    }

    takealtmaxx[pos][bc]  = 0;
    notakealtmaxx[pos][bc]=0;

    for(int w : E[pos])
    {
        if(w==parent) continue;
        nt = dfs(w, bc, pos);
        t = dfs(w, bc-1, pos) + sum;
        if(takei[pos][bc]!=-1&&takei[pos][bc]!=w)
        {
            takealtmaxx[pos][bc]=max(takealtmaxx[pos][bc], t);
        }
        if(notakei[pos][bc]!=-1&&notakei[pos][bc]!=w)
        {
            notakealtmaxx[pos][bc]=max(notakealtmaxx[pos][bc], nt);
        }
    }

    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;
}

int mx=0;
void meta_dfs(int pos, int parent)
{
    rep(i, v+1) mx = max(mx, dfs(pos, i, -1));
    for(int w : E[pos])
    {
        if(w==parent) continue;
        for(int i = 1; i<= v; i++)
        {
            mem[pos][i] = 0;
            if(takei[pos][i]!=w) mem[pos][i] = max(mem[pos][i], takemaxx[pos][i]-p[w]);
            else mem[pos][i] = max(mem[pos][i], takealtmaxx[pos][i]-p[w]);
            if(notakei[pos][i]!=w) mem[pos][i] = max(mem[pos][i], notakemaxx[pos][i]);
            else mem[pos][i] = max(mem[pos][i], notakealtmaxx[pos][i]);
        }

        mem[w].assign(v+1, -1);
        meta_dfs(w,pos);
    }
}

void dfs2(int pos, int par)
{
    int sum = 0;
    for(int w : E[pos])
    {
        sum+=p[w];
        if(w!=par) dfs2(w,pos);
    }
    totsum[pos]=sum;
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    cin>>n>>v;
    p.resize(n+1);
    rep(i, n) cin>>p[i+1];
    
    E.resize(n+1);
    
    rep(i,n-1)
    {
        signed a,b;
        cin>>a>>b;
        E[a].push_back(b);
        E[b].push_back(a);
    }
    dfs2(1,-1);
    //int maxx = dfs(1, v, -1);
    //if(n<=1000) maxx = bruteforce();
    //cout<<maxx<<"\n";
    
    mem.assign(n+1, vector<int>(v+1, -1));
    takei.assign(n+1, vector<signed>(v+1, -1));
    notakei.assign(n+1, vector<signed>(v+1, -1));
    takemaxx.assign(n+1, vector<int>(v+1, -1));
    notakemaxx.assign(n+1, vector<int>(v+1, -1));
    takealtmaxx.assign(n+1, vector<int>(v+1, -1));
    notakealtmaxx.assign(n+1, vector<int>(v+1, -1));

    meta_dfs(1, -1);
    cout<<mx<<"\n";
}

Subtask #1
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 588 KB Output is correct
2 Correct 1 ms 588 KB Output is correct
3 Incorrect 1 ms 588 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 588 KB Output is correct
2 Correct 1 ms 588 KB Output is correct
3 Incorrect 1 ms 588 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 30.0

# Verdict Execution time Memory Grader output
1 Execution timed out 4116 ms 510196 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 588 KB Output is correct
2 Correct 1 ms 588 KB Output is correct
3 Incorrect 1 ms 588 KB Output isn't correct
4 Halted 0 ms 0 KB -