Submission #826791

#	Time	Username	Problem	Language	Result	Execution time	Memory
826791		cig32	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	57 / 100	333 ms	262144 KiB

skyscraper

#include "bits/stdc++.h"
using namespace std;
#define double long double
const int MAXN = 14000000;
const int MAXN2 = 10400000;
const int MOD = 1e9 + 7;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
int bm(int b, int p) {
  if(p==0) return 1 % MOD;
  int r = bm(b, p >> 1);
  if(p&1) return (((r*r) % MOD) * b) % MOD;
  return (r*r) % MOD;
}
int inv(int b) { 
  return bm(b, MOD-2);
}
int fastlog(int x) {
  return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void printcase(int i) { cout << "Case #" << i << ": "; }
int n, m, s, nxt;
pair<int, int> cmds[MAXN];
int adj[MAXN];
int id;
int ps[MAXN2];
short cur[MAXN2];
int dq[MAXN];
int dist[MAXN2];
bitset<MAXN2>vis;
void add_command(int u, int v) {
  cmds[id] = {u,v};
  ps[u]++;
  id++;
}
void construct(int b, int p) { 
  for(int j=b%p; j<n; j+=p) {
    if(j+p < n) add_command(nxt + j/p, (nxt + j/p + 1) * 2 + 1); //adj[nxt + j/p].push_back((nxt + j/p + 1) * 2 + 1);
    if(j-p >= 0) add_command(nxt + j/p, (nxt + j/p - 1) * 2 + 1); //adj[nxt + j/p].push_back((nxt + j/p - 1) * 2 + 1);
    add_command(nxt + j/p, j * 2); //adj[nxt + j/p].push_back(j * 2 + 0);
  }
  add_command(b, (nxt + b/p) * 2); //adj[b].push_back((nxt + b/p) * 2 + 0);
  for(int j=b%p; j<n; j+=p) {
    nxt++;
  }
}
void solve(int tc) {
  cin >> n >> m;
  s = 50;//ceil(sqrt(n));
  nxt = n;
  int st, en;
  unordered_map<int, int> bruh[30001];
  for(int i=0; i<m; i++) {
    int b, p;
    cin >> b >> p;
    if(i == 0) st = b;
    if(i == 1) en = b;
    if(!bruh[p].count(b%p) && p<=s) {
      bruh[p][b%p] = nxt;
      construct(b, p);
    }
    else if(p<=s) {
      add_command(b, (bruh[p][b%p] + b/p) * 2);
    }
    else {
      for(int j=b%p; j<n; j+=p) {
    if(j+p < n && j >= b) add_command(nxt + j/p, (nxt + j/p + 1) * 2 + 1); //adj[nxt + j/p].push_back((nxt + j/p + 1) * 2 + 1);
    if(j-p >= 0 && j <= b) add_command(nxt + j/p, (nxt + j/p - 1) * 2 + 1); //adj[nxt + j/p].push_back((nxt + j/p - 1) * 2 + 1);
    add_command(nxt + j/p, j * 2); //adj[nxt + j/p].push_back(j * 2 + 0);
  }
  add_command(b, (nxt + b/p) * 2); //adj[b].push_back((nxt + b/p) * 2 + 0);
  for(int j=b%p; j<n; j+=p) {
    nxt++;
  }
    }
  }
  for(int i=1; i<MAXN2; i++) ps[i]+=ps[i-1];
  for(int i=0; i<MAXN2; i++) cur[i]=0;
  for(int i=0; i<id; i++) {
    int u = cmds[i].first, v = cmds[i].second;
    adj[cur[u]+(u==0?0:ps[u-1])] = v;
    cur[u]++;
  }
  int k = nxt;
  for(int i=0; i<k; i++) dist[i] = 1e9, vis[i] = 0;
  dist[st] = 0;
  int head=0, tail=1;
  dq[0]=st;
  while(head!=tail) {
    int f = dq[head];
    head=(head+1)%MAXN;
    if(!vis[f]) {
      vis[f] = 1;
      if(f==en)break;
      int l, r;
      if(f==0) l=0, r=ps[0]-1;
      else l=ps[f-1], r=ps[f]-1;
      for(int y=l; y<=r; y++) {
        int x = adj[y];
        if(!vis[x / 2] && dist[x / 2] > dist[f] + (x % 2)) {
          dist[x / 2] = dist[f] + (x % 2);
          if(x % 2 == 0) {
            head=(head+MAXN-1)%MAXN;
            dq[head]=x/2;
          }
          else dq[tail++]=x/2;
        }
      }
    }
  }
  cout<<(dist[en]==1e9?-1:dist[en])<<"\n";
}
int32_t main() {
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
}
// 勿忘初衷

Compilation message (stderr)

skyscraper.cpp: In function 'void solve(int)':
skyscraper.cpp:96:7: warning: 'en' may be used uninitialized in this function [-Wmaybe-uninitialized]
   96 |       if(f==en)break;
      |       ^~
skyscraper.cpp:90:8: warning: 'st' may be used uninitialized in this function [-Wmaybe-uninitialized]
   90 |   dq[0]=st;
      |   ~~~~~^~~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 14 / 14
• Subtask 4: 21 / 21
• Subtask 5: 0 / 43