Submission #520876

#	Time	Username	Problem	Language	Result	Execution time	Memory
520876		knon0501	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	936 ms	50000 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9;
int dist[30005][200];
int vis[30005][200];

vector<int> a[30005];
typedef pair<int,pair<int,int>> pp;
int n, m;
int main()
{
   // freopen("input.txt","r",stdin);
    cin.tie(0);
    ios_base::sync_with_stdio(0);
    cin >> n >> m;
    int t;
    int k;
    for (int i = 0; i < m; i++)
    {

        int x, y;
        cin >> x >> y;
        if (i == 0)
            k = x;
        if (i == 1)
            t = x;
        a[x].emplace_back(y);
    }
    int s=sqrt(n);
    for (int i = 0; i < n; i++)
        for(int j=0 ; j<=s ; j++)
            dist[i][j] = INF;
    dist[k][0] = 0;

    priority_queue<pp,vector<pp>,greater<pp>> Q;
    Q.push({0,{k,0}});

    while(!Q.empty()){
        auto x=Q.top(); Q.pop();
        int v=x.second.first;
        int w=x.second.second;
        int d=x.first;
        if(vis[v][w])continue;
        vis[v][w]=1;
        if(w==0){
            for(auto e: a[v]){
                if(e>s){
                    int cnt=0;
                    for(int i=v+e  ; i<n ; i+=e){
                        cnt++;
                        if(dist[i][0]>d+cnt){
                            dist[i][0]=d+cnt;
                            Q.push({dist[i][0],{i,0}});
                        }
                    }
                    cnt=0;
                    for(int i=v-e ; i>=0 ;i-=e){
                        cnt++;
                        if (dist[i][0] > d + cnt)
                        {
                            dist[i][0] = d + cnt;
                            Q.push({dist[i][0], {i, 0}});
                        }
                    }
                }
                else{
                    if(dist[v][e]>d){
                        dist[v][e]=d;
                        Q.push({d,{v,e}});
                    }
                }
            }    
        }
        else{
            if(v+w<n && dist[v+w][w]>d+1){
                dist[v+w][w]=d+1;
                Q.push({dist[v+w][w],{v+w,w}});
            }
            if(v-w>=0 && dist[v-w][w]>d+1){
                dist[v-w][w]=d+1;
                Q.push({dist[v-w][w],{v-w,w}});
            }
            if(dist[v][0]>d){
                dist[v][0]=d;
                Q.push({d,{v,0}});
            }
        }
    }
    if (dist[t][0] == INF)
        cout << -1;
    else
        cout << dist[t][0];
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:89:18: warning: 't' may be used uninitialized in this function [-Wmaybe-uninitialized]
   89 |     if (dist[t][0] == INF)
      |         ~~~~~~~~~^

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