Submission #99523

#	Time	Username	Problem	Language	Result	Execution time	Memory
99523		ae04071	Jakarta Skyscrapers (APIO15_skyscraper)	C++11	57 / 100	1069 ms	32632 KiB

skyscraper

#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
using pii=pair<int,int>;

int n,m;
vector<int> arr[30000];
queue<pair<pii,int>> que;
set<pii> vis;

inline int abs(int a) {return a<0 ? -a : a;}
void push_val(int a,int b,int c) {
    if(a+b<0 || a+b>=n) return;

    pii idx = pii(a+b, abs(b));
    if(vis.find(idx)!=vis.end()) return;
    vis.insert(idx);
    que.push({idx,c});
}
int main() {
    int ei;
    scanf("%d%d",&n,&m);
    for(int i=0,a,b;i<m;i++) {
        scanf("%d%d",&a,&b);
        arr[a].push_back(b);
        if(i==0) {
            vis.insert({a,0});
            que.push({{a,0},0});
        } else if(i==1) {
            ei = a;
        }
    }

    while(!que.empty()) {
        int cost=que.front().se, pos=que.front().fi.fi, pv=que.front().fi.se;
        que.pop();
        if(pos == ei) {
            printf("%d\n",cost);
            return 0;
        }
        while(!arr[pos].empty()) {
            int pp=arr[pos].back(); arr[pos].pop_back();
            push_val(pos,pp,cost+1); push_val(pos,-pp,cost+1);
        }
        push_val(pos,pv,cost+1); push_val(pos,-pv,cost+1);
    }
    puts("-1");
    
    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:23:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
skyscraper.cpp:25:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&a,&b);
         ~~~~~^~~~~~~~~~~~~~
skyscraper.cpp:38:9: warning: 'ei' may be used uninitialized in this function [-Wmaybe-uninitialized]
         if(pos == ei) {
         ^~

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