oj.uz

답안 #218173

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
218173 2020-04-01T11:28:32 Z Autoratch 구슬과 끈 (APIO14_beads) C++14
0 / 100
 9 ms 5120 KB 
#include <bits/stdc++.h>
using namespace std;

const int N = 2e5 + 1;

int n;
vector<pair<int,int> > adj[N];
int dp[N][4];

int mxx(int a,int b,int c){ return max(a,max(b,c)); }

void dfs(int u,int p)
{
    int mx = INT_MIN,mx2 = INT_MIN,mxc = INT_MIN,s1 = 0,ch = 0;
    dp[u][1] = INT_MIN;
    for(auto [d,v] : adj[u]) if(v!=p)
    {
        ch++;
        dfs(v,u);
        dp[u][0]+=mxx(dp[v][0],dp[v][2],dp[v][3]);
        if(dp[v][1]!=INT_MIN) s1+=dp[v][1]+d;
        if(dp[v][1]!=INT_MIN) dp[u][1] = max(dp[u][1],d+mxx(dp[v][0],dp[v][2],dp[v][3])-dp[v][1]-d);
        else dp[u][1] = max(dp[u][1],d+mxx(dp[v][0],dp[v][2],dp[v][3]));
        int tmp = max(mxx(dp[v][0],dp[v][2],dp[v][3]),d+dp[v][1]);   
        dp[u][2]+=tmp;
        if(d+max(dp[v][0],dp[v][2])-tmp>mx) mx2 = mx,mx = d+max(dp[v][0],dp[v][2])-tmp;
        else if(d+max(dp[v][0],dp[v][2])-tmp>mx2) mx2 = d+max(dp[v][0],dp[v][2])-tmp;
        if(d+mxx(dp[v][3],dp[v][3],dp[v][3])-tmp>mxc) mxc = d+mxx(dp[v][3],dp[v][3],dp[v][3])-tmp;
        dp[u][3]+=tmp;
    }
    dp[u][1]+=s1;
    if(ch>=2) dp[u][3]+=mxx(0,mx+mx2,mx+mxc);
    else dp[u][3] = INT_MIN;
}

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

    cin >> n;
    for(int i = 0;i < n-1;i++)
    {
        int a,b,d;
        cin >> a >> b >> d;
        adj[a].push_back({d,b});
        adj[b].push_back({d,a});
    }
    dfs(1,0);
    cout << mxx(dp[1][0],dp[1][2],dp[1][3]);
}

Compilation message

beads.cpp: In function 'void dfs(int, int)':
beads.cpp:16:14: warning: decomposition declaration only available with -std=c++1z or -std=gnu++1z
     for(auto [d,v] : adj[u]) if(v!=p)
              ^

Subtask #1
0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 7 ms 4992 KB Output is correct
4 Correct 9 ms 5120 KB Output is correct
5 Incorrect 7 ms 5120 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 7 ms 4992 KB Output is correct
4 Correct 9 ms 5120 KB Output is correct
5 Incorrect 7 ms 5120 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 7 ms 4992 KB Output is correct
4 Correct 9 ms 5120 KB Output is correct
5 Incorrect 7 ms 5120 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 43.0

# 결과 실행 시간 메모리 Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 7 ms 4992 KB Output is correct
4 Correct 9 ms 5120 KB Output is correct
5 Incorrect 7 ms 5120 KB Output isn't correct
6 Halted 0 ms 0 KB -