Submission #361472

#	Time	Username	Problem	Language	Result	Execution time	Memory
361472		alireza_kaviani	Jakarta Skyscrapers (APIO15_skyscraper)	C++11	100 / 100	551 ms	134380 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;

#define all(x)						(x).begin(),(x).end()
#define X							first
#define Y							second
#define sep							' '
#define endl						'\n'
#define SZ(x)						ll(x.size())

const ll MAXN = 3e4 + 10;
const ll SQ = 200;
const ll LOG = 22;
const ll INF = 8e18;
const ll MOD = 1e9 + 7; //998244353; //1e9 + 9;

int n , m , ptr;
int q[MAXN * SQ * 4] , dist[MAXN * SQ * 2] , pos[MAXN * SQ * 2] , len[MAXN * SQ * 2];
vector<int> adj[MAXN];

void BFS(int v){
	fill(dist , dist + MAXN * SQ * 2 , MOD);
	dist[v] = 0;
	int ql = MAXN * SQ * 2 , qr = ql;
	q[qr++] = v;
	while(ql < qr){
		int v = q[ql++];
		if(v < n){
			for(int u : adj[v]){
				if(dist[u] > dist[v]){
					dist[u] = dist[v];
					q[--ql] = u;
				}
			}
			continue;
		}
		if(dist[pos[v]] > dist[v]){
			dist[pos[v]] = dist[v];
			q[--ql] = pos[v];
		}
		if(v < n + m)	continue;
		for(int i = -1 ; i <= 1 ; i += 2){
			int u = v + i * (len[v] < 0 ? -1 : len[v]) , p = pos[v] + i * len[v];
			if(p < 0 || p >= n)	continue;
			if(dist[u] > dist[v] + 1){
				dist[u] = dist[v] + 1;
				q[qr++] = u;
			}
		}
	}
}

int main() {
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

	cin >> n >> m;
	ptr = n + m;
	for(int i = 1 ; i < SQ ; i++){
		for(int j = 0 ; j < n ; j++){
			pos[ptr + j] = j;
			len[ptr + j] = i;
		}
		ptr += n;
	}
	for(int i = 0 ; i < m ; i++){
		int x , y;
		cin >> x >> y;
		adj[x].push_back(n + i);
		if(y < SQ){
			pos[n + i] = m + n * y + x;
			continue;
		}
		int z = x % y;
		for(int j = z ; j < n ; j += y){
			pos[ptr] = j;
			len[ptr] = -y;
			if(j == x){
				pos[n + i] = ptr;
			}
			ptr++;
		}
	}
	BFS(n);
	cout << (dist[n + 1] == MOD ? -1 : dist[n + 1]) << endl;

    return 0;
}
/*

*/

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