Submission #155396

#	Time	Username	Problem	Language	Result	Execution time	Memory
155396		dantoh000	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	0 / 100	20 ms	21436 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> ii;
unordered_map<int,vector<ii> > adjlist;
int dist[5200000];
vector<int> big[30005];
int n,m;
int k;
int s;
int e;
int main(){
    scanf("%d%d",&n,&m);
    k = sqrt(n);
    for (int i = 0; i < m; i++){
        int b,p;
        scanf("%d%d",&b,&p);
        if (i == 0) s = b;
        if (i == 1) e= b;
        if (p >= k){
            big[b].push_back(p);
        }
        else{
            adjlist[b*k].push_back(ii(b*k+p,0));
            adjlist[b*k+p].push_back(ii(b*k,0));
        }
    }
    priority_queue<ii,vector<ii>,greater<ii> > pq;
    memset(dist,-1,sizeof(dist));
    dist[s*k] = 0;
    pq.push(ii(0,s*k));
    while (pq.size()){
        ii cur = pq.top(); pq.pop();
        int d = cur.first, u = cur.second;
        if (e*k == u) break;
        //printf("%d %d\n",d,u);
        if (dist[u] > d) continue;
        if (u % k == 0){
            for (auto x : big[u/k]){
                for (int i = 1; i <= k; i++){
                    int v = u-(i*x)*k;
                    if (v >= 0 && (dist[v] == -1 || dist[v] > dist[u]+i)){
                        dist[v] = dist[u]+i;
                        pq.push(ii(dist[v],v));
                    }
                    v = u+(i*x)*k;
                    if (v < n*k && (dist[v] == -1 || dist[v] > dist[u]+i)){
                        dist[v] = dist[u]+i;
                        pq.push(ii(dist[v],v));
                    }
                }
            }
        }
        for (auto v : adjlist[u]){
            //printf("maybe %d %d\n",v.first,v.second);
            if (dist[v.first] == -1 || dist[v.first] > dist[u]+v.second){
                dist[v.first] = dist[u]+v.second;
                pq.push(ii(dist[v.first],v.first));
            }
        }

    }
    printf("%d",dist[e*k]);
    return 0;


}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:12:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
skyscraper.cpp:16:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&b,&p);
         ~~~~~^~~~~~~~~~~~~~

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