Submission #122436

#	Time	Username	Problem	Language	Result	Execution time	Memory
122436		IOrtroiii	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	160 ms	75984 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

const int N = 30030;
const int MG = 200;
const int inf = 1e9;

int d[N];
int b[N], p[N];
bool was[N][MG];
bool useless[N];
vector<pair<int, int>> g[N];

int main() {
   int n, m;
   scanf("%d %d", &n, &m);
   for (int i = 0; i < m; ++i) {
      scanf("%d %d", b + i, p + i);
      if (p[i] < MG) {
         if (was[b[i]][p[i]]) {
            useless[i] = true;
         } else {
            was[b[i]][p[i]] = true;
         }
      }
   }
   for (int i = 0; i < m; ++i) {
      if (useless[i]) continue;
      for (int j = 1; ; ++j) {
         int v = b[i] - j * p[i];
         if (v < 0) break;
         g[b[i]].emplace_back(v, j);
         if (p[i] < MG && was[v][p[i]]) {
            break;
         }
      }
      for (int j = 1; ; ++j) {
         int v = b[i] + j * p[i];
         if (v >= n) break;
         g[b[i]].emplace_back(v, j);
         if (p[i] < MG && was[v][p[i]]) {
            break;
         }
      }
   }
   for (int i = 0; i < n; ++i) {
      d[i] = inf;
   }
   priority_queue<pair<int, int>> q;
   d[b[0]] = 0;
   q.emplace(0, b[0]);
   while (!q.empty()) {
      int du, u;
      tie(du, u) = q.top();
      q.pop();
      du = -du;
      if (d[u] != du) {
         continue;
      }
      for (auto e : g[u]) {
         int v, w;
         tie(v, w) = e;
         if (d[v] > d[u] + w) {
            d[v] = d[u] + w;
            q.emplace(-d[v], v);
         }
      }
   }
   printf("%d\n", (d[b[1]] == inf ? -1 : d[b[1]]));
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:17:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d %d", &n, &m);
    ~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:19:12: 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: 43 / 43