Submission #232015

#	Time	Username	Problem	Language	Result	Execution time	Memory
232015		nicolaalexandra	Chase (CEOI17_chase)	C++14	0 / 100	538 ms	336888 KiB

chase

#include <bits/stdc++.h>
#define DIM 100002
#define INF 2000000000000000000LL
using namespace std;
vector <int> L[DIM];
int v[DIM],fth[DIM];
long long sum[DIM],maxi;
int n,x,y,i,j,nr,k;

long long dp_up[DIM][102][2], dp_down[DIM][102][2];
/// dp_up[nod][i] = care e suma maxima daca incep undeva in subarborele lui nod,
/// ajung in nod si am consumat maxim i boabe
/// dp_down[nod][i] = la fel doar ca incep din nod si ma duc in jos
void dfs (int nod, int tata){

    int ok = 0;
    fth[nod] = tata;
    for (auto vecin : L[nod])
        if (vecin != tata){
            ok = 1;
            dfs (vecin,nod);
        }


    dp_down[nod][1][1] = dp_up[nod][1][1] = sum[nod];

    for (auto vecin : L[nod]){
        if (vecin == tata)
            continue;

        /// dp_down + dp_up
        for (int i=0;i<=nr;i++){
            maxi = max (maxi,dp_down[nod][i][0] + dp_up[vecin][nr-i][0]);
            maxi = max (maxi,dp_down[nod][i][0] + dp_up[vecin][nr-i][1]);
            /// daca as pune in nod
            maxi = max (maxi,dp_down[nod][i][1] + dp_up[vecin][nr-i][0] - v[vecin]);
            maxi = max (maxi,dp_down[nod][i][1] + dp_up[vecin][nr-i][1] - v[vecin]);

            /// acum fac pe invers
            maxi = max (maxi,dp_down[vecin][i][0] + dp_up[nod][nr-i][0]);
            maxi = max (maxi,dp_down[vecin][i][0] + dp_up[nod][nr-i][1]);

            maxi = max (maxi,dp_down[vecin][i][1] + dp_up[nod][nr-i][0] - v[nod]);
            maxi = max (maxi,dp_down[vecin][i][1] + dp_up[nod][nr-i][1] - v[nod]);
        }

        for (int i=1;i<=nr;i++){

            /// vin de jos, nu mai conteaza nimic din ce am in nod, pt ca nu influenteaza
            dp_up[nod][i][0] = max (dp_up[nod][i][0], dp_up[nod][i-1][0]);
            dp_up[nod][i][0] = max (dp_up[nod][i][0], max(dp_up[vecin][i][0],dp_up[vecin][i][1]));

            /// cand pun boaba in i trb sa am grija sa scad valoarea din fiul in care ma aflu
            dp_up[nod][i][1] = max (dp_up[nod][i][1], dp_up[nod][i-1][1]);
            dp_up[nod][i][1] = max (dp_up[nod][i][1], dp_up[vecin][i-1][0] + sum[nod] - v[vecin]);
            dp_up[nod][i][1] = max (dp_up[nod][i][1], dp_up[vecin][i-1][1] + sum[nod] - v[vecin]);


            /// acum ma duc spre vecin
            dp_down[nod][i][0] = max (dp_down[nod][i][0], dp_down[nod][i-1][0]);
            dp_down[nod][i][0] = max (dp_down[nod][i][0], dp_down[vecin][i][0]);
            dp_down[nod][i][0] = max (dp_down[nod][i][0], dp_down[vecin][i][1] - v[nod]);

            dp_down[nod][i][1] = max (dp_down[nod][i][1], dp_down[nod][i-1][1]);
            dp_down[nod][i][1] = max (dp_down[nod][i][1], dp_down[vecin][i-1][0] + sum[nod]);
            dp_down[nod][i][1] = max (dp_down[nod][i][1], dp_down[vecin][i-1][1] + sum[nod] - v[vecin]);

        }
    }
}

int main (){

    //ifstream cin ("date.in");
    //ofstream cout ("date.out");

    cin>>n>>nr;
    for (i=1;i<=n;i++)
        cin>>v[i];
    for (i=1;i<n;i++){
        cin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }

    for (i=1;i<=n;i++){
        //sum[i] = v[i];
        for (auto it : L[i])
            sum[i] += v[it];
    }

    if (nr == 0){
        cout<<0;
        return 0;
    }

    if (nr == 1){
        long long maxi = 0;
        for (i=1;i<=n;i++)
            maxi = max (maxi,sum[i] - v[i]);
        cout<<maxi;
        return 0;
    }

    for (i=1;i<=n;i++)
        for (j=1;j<=nr;j++){
            dp_down[i][j][0] = dp_down[i][j][1] = -INF;
            dp_up[i][j][0] = dp_up[i][j][1] = -INF;
        }

    dfs (1,0);

    for (i=1;i<=n;i++)
        for (j=1;j<=nr;j++){
            maxi = max (maxi,max(dp_down[i][j][0],dp_down[i][j][1]));
            maxi = max (maxi,max(dp_up[i][j][0],dp_up[i][j][1]));
        }

    cout<<maxi;


    return 0;
}

Compilation message (stderr)

chase.cpp: In function 'void dfs(int, int)':
chase.cpp:16:9: warning: variable 'ok' set but not used [-Wunused-but-set-variable]
     int ok = 0;
         ^~

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