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Submission #261384

# Submission time Handle Problem Language Result Execution time Memory
261384 2020-08-11T16:56:25 Z Nightlight Aesthetic (NOI20_aesthetic) C++14
35 / 100
 2000 ms 72436 KB 
#include <cstdio>
#include <queue>
#include <cstring>
#define pii pair<long long, int>
using namespace std;
 
int N, M;
vector<pii> adj[300005];
priority_queue<pii, vector<pii>, greater<pii>> pq;
long long dist[2][300005];
int U[300005], V[300005];
bool can[300005], ada[300005];
long long W[300005], best[300005];
vector<pair<int, int>> adj2[300005];
int disc[300005], low[300005], waktu, need;
long long p1[300005], p2[300005], pp1[300005], pp2[300005];
bool ok;
 
void BFS(int id, int st) {
  memset(ada, 0, sizeof(ada));
  pq.emplace(0LL, st);
  dist[id][st] = 0;
  int u, v;
  long long len, w;
  while(!pq.empty()) {
    u = pq.top().second;
    len = pq.top().first;
    pq.pop();
    if(len != dist[id][u]) continue;
    for(pii now : adj[u]) {
      v = now.second;
      w = now.first;
      if(dist[id][v] > len + w) {
        dist[id][v] = len + w;
        pq.emplace(dist[id][v], v);
      }
    }
  }
}
 
void DFS(int u, int p) {
  disc[u] = low[u] = ++waktu;
  int v, id;
  for(pair<int, int> now : adj2[u]) {
    id = now.second;
    if(ada[id] == 0) continue;
    v = now.first; 
    if(disc[v] <= need) {
      DFS(v, u);
      if(low[v] > disc[u] && can[id] && disc[N] >= disc[v] && disc[N] <= waktu) {
        ok = 1;
      }else low[u] = min(low[u], low[v]);
    }else if(p != v) {
      low[u] = min(low[u], disc[v]);
    }
  }
}
 
bool check(long long now) {
  ok = 0;
  need = waktu;
  for(int i = 1; i <= M; i++) {
    if(p1[i] > now && p2[i] > now) ada[i] = 0;
    else ada[i] = 1;
    if(pp1[i] > now && pp2[i] > now) can[i] = 1;
    else can[i] = 0;
  }
  DFS(1, 0);
  if(disc[N] <= need) return 1;
  if(ok) return 1;
  return 0;
}
 
int main() {
  memset(dist, 0x3f3f3f3f, sizeof(dist));
  scanf("%d %d", &N, &M);
  int u, v;
  long long w;
  for(int i = 1; i <= M; i++) {
    scanf("%d %d %lld", &u, &v, &w);
    U[i] = u, V[i] = v, W[i] = w;
    adj[u].emplace_back(w, v);
    adj[v].emplace_back(w, u);
    adj2[u].emplace_back(v, i);
    adj2[v].emplace_back(u, i);
  }
  for(int i = M - 1; i > 0; i--) {
    best[i] = max(best[i + 1], W[i + 1]);
  }
  BFS(0, 1);
  BFS(1, N);
  for(int i = 1; i <= M; i++) {
    p1[i] = dist[0][U[i]] + W[i] + dist[1][V[i]];
    p2[i] = dist[0][V[i]] + W[i] + dist[1][U[i]];
    pp1[i] = dist[0][U[i]] + best[i] + W[i] + dist[1][V[i]];
    pp2[i] = dist[0][V[i]] + best[i] + W[i] + dist[1][U[i]];
  }
  long long l = dist[0][N], r = dist[0][N] + 1000000000, res = dist[0][N], mid;
  while(l <= r) {
    mid = (l + r) >> 1;
    if(check(mid)) {
      l = mid + 1;
      res = l;
    }else r = mid - 1;
  }
  printf("%lld\n", res);
}

Compilation message

Aesthetic.cpp: In function 'int main()':
Aesthetic.cpp:76:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &N, &M);
   ~~~~~^~~~~~~~~~~~~~~~~
Aesthetic.cpp:80:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %lld", &u, &v, &w);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 19456 KB Output is correct
2 Correct 14 ms 19456 KB Output is correct
3 Correct 14 ms 19456 KB Output is correct
4 Correct 14 ms 19456 KB Output is correct
5 Correct 14 ms 19456 KB Output is correct
6 Correct 14 ms 19456 KB Output is correct
7 Correct 14 ms 19456 KB Output is correct
8 Correct 14 ms 19456 KB Output is correct

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 19456 KB Output is correct
2 Correct 14 ms 19456 KB Output is correct
3 Correct 14 ms 19456 KB Output is correct
4 Correct 14 ms 19456 KB Output is correct
5 Correct 14 ms 19456 KB Output is correct
6 Correct 14 ms 19456 KB Output is correct
7 Correct 14 ms 19456 KB Output is correct
8 Correct 14 ms 19456 KB Output is correct
9 Correct 14 ms 19712 KB Output is correct
10 Correct 17 ms 20000 KB Output is correct
11 Correct 17 ms 19712 KB Output is correct
12 Correct 20 ms 19712 KB Output is correct
13 Correct 16 ms 19840 KB Output is correct
14 Correct 16 ms 19840 KB Output is correct
15 Correct 17 ms 19840 KB Output is correct
16 Correct 17 ms 19840 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 941 ms 65304 KB Output is correct
2 Correct 900 ms 65468 KB Output is correct
3 Correct 948 ms 65016 KB Output is correct
4 Correct 946 ms 65036 KB Output is correct
5 Correct 981 ms 65272 KB Output is correct
6 Correct 907 ms 66368 KB Output is correct
7 Correct 922 ms 65864 KB Output is correct
8 Correct 886 ms 66452 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 926 ms 66268 KB Output is correct
2 Correct 926 ms 65744 KB Output is correct
3 Correct 881 ms 65028 KB Output is correct
4 Correct 852 ms 64888 KB Output is correct
5 Correct 896 ms 65528 KB Output is correct
6 Correct 881 ms 65372 KB Output is correct
7 Correct 919 ms 65528 KB Output is correct
8 Correct 957 ms 66116 KB Output is correct

Subtask #5
0 / 16.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2094 ms 72436 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 22.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2094 ms 72436 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #7
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 19456 KB Output is correct
2 Correct 14 ms 19456 KB Output is correct
3 Correct 14 ms 19456 KB Output is correct
4 Correct 14 ms 19456 KB Output is correct
5 Correct 14 ms 19456 KB Output is correct
6 Correct 14 ms 19456 KB Output is correct
7 Correct 14 ms 19456 KB Output is correct
8 Correct 14 ms 19456 KB Output is correct
9 Correct 14 ms 19712 KB Output is correct
10 Correct 17 ms 20000 KB Output is correct
11 Correct 17 ms 19712 KB Output is correct
12 Correct 20 ms 19712 KB Output is correct
13 Correct 16 ms 19840 KB Output is correct
14 Correct 16 ms 19840 KB Output is correct
15 Correct 17 ms 19840 KB Output is correct
16 Correct 17 ms 19840 KB Output is correct
17 Correct 941 ms 65304 KB Output is correct
18 Correct 900 ms 65468 KB Output is correct
19 Correct 948 ms 65016 KB Output is correct
20 Correct 946 ms 65036 KB Output is correct
21 Correct 981 ms 65272 KB Output is correct
22 Correct 907 ms 66368 KB Output is correct
23 Correct 922 ms 65864 KB Output is correct
24 Correct 886 ms 66452 KB Output is correct
25 Correct 926 ms 66268 KB Output is correct
26 Correct 926 ms 65744 KB Output is correct
27 Correct 881 ms 65028 KB Output is correct
28 Correct 852 ms 64888 KB Output is correct
29 Correct 896 ms 65528 KB Output is correct
30 Correct 881 ms 65372 KB Output is correct
31 Correct 919 ms 65528 KB Output is correct
32 Correct 957 ms 66116 KB Output is correct
33 Execution timed out 2094 ms 72436 KB Time limit exceeded
34 Halted 0 ms 0 KB -