Submission #90136

#	Time	Username	Problem	Language	Result	Execution time	Memory
90136		mirbek01	Biochips (IZhO12_biochips)	C++17	0 / 100	10 ms	12920 KiB

biochips

# include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 2;

int n, m, rt, a[N], x[N], tin[N], tout[N], timer, cur;
long long dp[505][N], pref[N], suff[N];
vector <int> g[N];

void dfs1(int v){
      tin[v] = ++  timer;
      for(int to : g[v]){
            dfs1(to);
      }
      tout[v] = timer;
}

void dfs(int v){
      for(int to : g[v]){
            dfs(to);
      }
      dp[cur][v] = max(pref[tin[v] - 1] + suff[tout[v] + 1] + x[v], dp[cur][v]);
}

int main(){
      cin >> n >> m;

      for(int i = 1; i <= n; i ++){
            int p;
            cin >> p >> x[i];
            if(!p)
                  rt = i;
            else {
                  g[p].push_back(i);
            }
      }

      dfs1(rt);

      for(int i = 0; i <= m; i ++){
            for(int j = 0; j < N; j ++)
                  dp[i][j] = -1e18;
      }

      for(int i = 1; i <= n; i ++)
            dp[1][i] = x[i];

      for(int i = 2; i <= m; i ++){
            cur = i;
            dfs(rt);
            for(int j = 0; j <= n + 1; j ++)
                  pref[j] = suff[j] = -1e18;
            for(int j = 1; j <= n; j ++){
                  pref[ tout[j] ] = max(pref[ tout[j] ], dp[cur][j]);
                  suff[ tin[j] ] = max(suff[ tin[j] ], dp[cur][j]);
            }
            for(int j = 1; j <= n; j ++)
                  pref[j] = max(pref[j - 1], pref[j]);
            for(int j = n; j >= 1; j --)
                  suff[j] = max(suff[j + 1], suff[j]);
      }

      long long ans = 0;

      for(int i = 1; i <= n; i ++)
            ans = max(ans, pref[i]);

      cout << ans << endl;
}

• Subtask 1: 0 / 100