Submission #1050313

#	Time	Username	Problem	Language	Result	Execution time	Memory
1050313		NeroZein	Jobs (BOI24_jobs)	C++17	43 / 100	2060 ms	34136 KiB

Main

#include "bits/stdc++.h"
using namespace std;
 
#ifdef Nero
#include "Deb.h"
#else
#define debug(...)
#endif
 
const int N = 3e5 + 5;
 
int x[N];
int p[N];
bool taken[N];
bool active[N];
vector<int> g[N];
long long sum[N];
long long best[N];
long long nbest[N];
long long min_suf[N];
long long min_seg[N];
 
void dfs(int v) {
  min_suf[v] = min(0LL, min_suf[v] + x[v]); 
  min_seg[v] = min(min_seg[v], min_suf[v]);
  for (int u : g[v]) {
    min_suf[u] = min_suf[v];
    min_seg[u] = min_seg[v]; 
    dfs(u);
  }
}

void activate(int v) {//no child is activated before a parent
  //debug(v); 
  int b = x[v]; 
  nbest[v] = b; 
  active[v] = true;
  while (v != 0) {
    nbest[p[v]] = best[p[v]] - max(0LL, best[v]);
    nbest[p[v]] += max(0LL, nbest[v]);
    best[v] = nbest[v];
    //debug(v, best[v]);
    v = p[v]; 
  }
  //cout << '\n';
}

void dfs2(int v) {
  taken[v] = true; 
  for (int u : g[v]) {
    if (best[u] > 0) {
      dfs2(u);
    } else {
      p[u] = 0;
    }
  }
}
 
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n;
  long long s;
  cin >> n >> s;
  for (int i = 1; i <= n; ++i) {
    cin >> x[i] >> p[i];
    g[p[i]].push_back(i);
  }
  long long cur = s; 
  for (int rep = 0; rep < n; ++rep) {
    for (int i = 1; i <= n; ++i) {
      if (p[i] == 0 && !taken[i]) {
        min_suf[i] = min_seg[i] = 0;
        dfs(i);
      }
    }
    for (int i = 1; i <= n; ++i) {
      if (!active[i] && !taken[i] && cur + min_seg[i] >= 0) {
        activate(i); 
      }
    }
    for (int i = 1; i <= n; ++i) {
      if (!taken[i] && p[i] == 0 && best[i] > 0) {
        //debug(i, best[i]); 
        cur += best[i];
        dfs2(i);
        break; 
      }
    }
  }
  cout << cur - s << '\n'; 
  return 0;
}

• Subtask 1: 0 / 11
• Subtask 2: 14 / 14
• Subtask 3: 0 / 15
• Subtask 4: 29 / 29
• Subtask 5: 0 / 31