Submission #124192

#	Time	Username	Problem	Language	Result	Execution time	Memory
124192		naderjemel	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	10 / 100	2 ms	504 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define INF 1e9
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<pair<int,int> > vii;
 
int n,m;
vector<vi> ns;
bitset<30001> dp[30001],vis;
queue<pair<ii,int> > q;
void solve(int pos, int u, int d, int p){
	if(pos<0 || pos>=n) return;
	if(dp[pos][p]) return;
	dp[pos][p]=true;
	q.push(mp(mp(d+1,pos),p));
}
 
void add(int u, int d){
	for(int i:ns[u]){
		if(!dp[u][i]);
		q.push(mp(mp(d,u),i));
	}
	vis[u]=true;
}
int main(){
	//printf("here\n");
	scanf("%d%d",&n,&m);
	ns.assign(n+2,vi());
	int n1;
	int nf;
	for(int i=0;i<m;i++){
		int x,y;
		scanf("%d%d",&x,&y);
		if(!i) n1=x;
		if(i==1) nf=x;
		ns[x].pb(y);
		//jm[i]=y;
	}
	//for(int i=0;i<n;i++) printf("%d ", dis[n1][i]); printf("\n");	
	for(int i:ns[n1]){
		dp[n1][i]=true;
		q.push(mp(mp(0,n1),i));
	}
	while(!q.empty()){
		int u=q.front().fi.se;
		int d=q.front().fi.fi;
		int p=q.front().se;
		q.pop();
		if(u==nf){
			printf("%d\n", d);
			return 0;
		}
		solve(u+p,u,d,p);
		//printf("%d %d\n",u,p);
		solve(u-p,u,d,p);
 		if(!vis[u]) add(u,d);
	}
	//printf("%d %d\n", n1,nf);
	printf("-1\n");
	return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:33:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~
skyscraper.cpp:39:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&x,&y);
   ~~~~~^~~~~~~~~~~~~~
skyscraper.cpp:46:17: warning: 'n1' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(int i:ns[n1]){
                 ^
skyscraper.cpp:55:3: warning: 'nf' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(u==nf){
   ^~

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