Submission #253933

#	Time	Username	Problem	Language	Result	Execution time	Memory
253933		ChrisT	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	57 / 100	214 ms	166776 KiB

skyscraper

    #include<bits/stdc++.h>
    #define hsh(x,y) (x)<<15|(y)
    using namespace std;
    const int MN = 30005;
    int b[MN], p[MN];
    pair<int,int> dq[11000000];
    bitset<300000000> vis;
    vector<int> st[MN];
    int main () {
      int n,m;
      scanf ("%d %d",&n,&m);
      for (int i = 0; i < m; i++) {
        scanf ("%d %d",&b[i],&p[i]);
        st[b[i]].push_back(i);
      }
      int l = n, r = l + 1;
      dq[l] = {hsh(b[0],p[0]),0};
      while (l < r) {
        int cur = dq[l].first>>15, power = dq[l].first & 0x7FFF, dist = dq[l].second; ++l;
        if (cur == b[1]) return !printf ("%d\n",dist);
        for (int i : st[cur]) if (!vis[hsh(cur,p[i])]) {
          vis[hsh(cur,p[i])] = 1;
          dq[--l] = {hsh(cur,p[i]),dist};
        }
        st[cur].clear();
        if (cur >= power && !vis[hsh(cur-power,power)]) {
          vis[hsh(cur-power,power)] = 1;
          dq[r++] = {hsh(cur-power,power),dist+1};
        }
        if (cur + power < n && !vis[hsh(cur+power,power)]) {
          vis[hsh(cur+power,power)] = 1;
          dq[r++] = {hsh(cur+power,power),dist+1};
        }
      }
      printf ("-1\n");
      return 0;
    }

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:11:13: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
       scanf ("%d %d",&n,&m);
       ~~~~~~^~~~~~~~~~~~~~~
skyscraper.cpp:13:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf ("%d %d",&b[i],&p[i]);
         ~~~~~~^~~~~~~~~~~~~~~~~~~~~

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