Submission #1825705


Source Code Expand

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;

const int maxn = 2e5;

int n, son[maxn][2];
long long len[maxn], lim;
typedef pair<long long, long long> Pair;
vector<Pair> set[maxn];

void Combine(vector<Pair> &s, int u, int v) {
  s.clear();
  if (set[u].empty()) {
    return;
  }

  // u -> v
  int j = 0;
  for (int i = 0; i < set[u].size(); ++i) {
    if (set[u][i].second + len[u] + set[v][j].first + len[v] > lim) {
      continue;
    }
    while (j + 1 < set[v].size() &&
           set[u][i].second + len[u] + set[v][j + 1].first + len[v] <= lim) {
      ++j;
    }
    s.push_back({set[u][i].first + len[u], set[v][j].second + len[v]});
  }
  int mid = s.size();

  // v -> u
  j = set[v].size() - 1;
  for (int i = set[u].size() - 1; i >= 0; --i) {
    if (set[v][j].second + len[v] + set[u][i].first + len[u] > lim) {
      continue;
    }
    while (j - 1 >= 0 &&
           set[v][j - 1].second + len[v] + set[u][i].first + len[u] <= lim) {
      --j;
    }
    s.push_back({set[v][j].first + len[v], set[u][i].second + len[u]});
  }
  reverse(s.begin() + mid, s.end());
  inplace_merge(s.begin(), s.begin() + mid, s.end());

  mid = 0;
  for (int i = 0; i < s.size(); ++i) {
    if (i == 0 || s[i].second < s[i - 1].second) {
      s[mid++] = s[i];
    }
  }
  s.resize(mid);
}

bool Check(void) {
  for (int i = n - 1; i >= 0; --i) {
    if (son[i][0] == -1) {
      set[i] = {{0, 0}};
    } else {
      int &u = son[i][0], &v = son[i][1];
      if (set[u].size() > set[v].size()) {
        swap(u, v);
      }
      Combine(set[i], u, v);
    }
  }
  return set[0].size() > 0;
}

int main(void) {
  scanf("%d", &n);
  memset(son, -1, sizeof son);
  for (int i = 1; i < n; ++i) {
    int par;
    scanf("%d%lld", &par, len + i);
    --par;
    swap(son[par][0], son[par][1]);
    son[par][0] = i;
  }
  long long low = 0, high = (long long)maxn * maxn;
  while (low < high) {
    lim = low + high >> 1;
    if (Check()) {
      high = lim;
    } else {
      low = lim + 1;
    }
  }
  printf("%lld\n", low);
  return 0;
}

Submission Info

Submission Time
Task E - Shik and Travel
User orbitingflea
Language C++14 (GCC 5.4.1)
Score 1400
Code Size 2185 Byte
Status AC
Exec Time 394 ms
Memory 30980 KB

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:74:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n);
                  ^
./Main.cpp:78:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%lld", &par, len + i);
                                   ^

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 1400 / 1400
Status
AC × 4
AC × 54
Set Name Test Cases
Sample example0.txt, example1.txt, example2.txt, example3.txt
All 000.txt, 001.txt, 002.txt, 003.txt, 004.txt, 005.txt, 006.txt, 007.txt, 008.txt, 009.txt, 010.txt, 011.txt, 012.txt, 013.txt, 014.txt, 015.txt, 016.txt, 017.txt, 018.txt, 019.txt, 020.txt, 021.txt, 022.txt, 023.txt, 024.txt, 025.txt, 026.txt, 027.txt, 028.txt, 029.txt, 030.txt, 031.txt, 032.txt, 033.txt, 034.txt, 035.txt, 036.txt, 037.txt, 038.txt, 039.txt, 040.txt, 041.txt, 042.txt, 043.txt, 044.txt, 045.txt, 046.txt, 047.txt, 048.txt, 049.txt, example0.txt, example1.txt, example2.txt, example3.txt
Case Name Status Exec Time Memory
000.txt AC 8 ms 8064 KB
001.txt AC 8 ms 8064 KB
002.txt AC 8 ms 8064 KB
003.txt AC 8 ms 8064 KB
004.txt AC 8 ms 8064 KB
005.txt AC 8 ms 8064 KB
006.txt AC 8 ms 8064 KB
007.txt AC 8 ms 8064 KB
008.txt AC 8 ms 8064 KB
009.txt AC 8 ms 8064 KB
010.txt AC 272 ms 13952 KB
011.txt AC 288 ms 16000 KB
012.txt AC 277 ms 13952 KB
013.txt AC 279 ms 13952 KB
014.txt AC 274 ms 13952 KB
015.txt AC 288 ms 13952 KB
016.txt AC 277 ms 13952 KB
017.txt AC 274 ms 13952 KB
018.txt AC 277 ms 13952 KB
019.txt AC 274 ms 13824 KB
020.txt AC 269 ms 13952 KB
021.txt AC 279 ms 13824 KB
022.txt AC 278 ms 13952 KB
023.txt AC 284 ms 13952 KB
024.txt AC 279 ms 13952 KB
025.txt AC 278 ms 13824 KB
026.txt AC 245 ms 13312 KB
027.txt AC 268 ms 13952 KB
028.txt AC 246 ms 13312 KB
029.txt AC 246 ms 13312 KB
030.txt AC 272 ms 14848 KB
031.txt AC 310 ms 14848 KB
032.txt AC 394 ms 14848 KB
033.txt AC 268 ms 14848 KB
034.txt AC 273 ms 14848 KB
035.txt AC 296 ms 14848 KB
036.txt AC 261 ms 14720 KB
037.txt AC 259 ms 14080 KB
038.txt AC 267 ms 14848 KB
039.txt AC 219 ms 13056 KB
040.txt AC 266 ms 29436 KB
041.txt AC 299 ms 30716 KB
042.txt AC 299 ms 30844 KB
043.txt AC 297 ms 30980 KB
044.txt AC 172 ms 13056 KB
045.txt AC 209 ms 13056 KB
046.txt AC 203 ms 13056 KB
047.txt AC 203 ms 13056 KB
048.txt AC 203 ms 13056 KB
049.txt AC 4 ms 7936 KB
example0.txt AC 4 ms 7936 KB
example1.txt AC 4 ms 7936 KB
example2.txt AC 4 ms 7936 KB
example3.txt AC 4 ms 7936 KB