Cod sursa(job #3228072)

Utilizator verde.cristian2005Verde Flaviu-Cristian verde.cristian2005 Data 5 mai 2024 14:25:44
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.74 kb
#include <bits/stdc++.h>
using namespace std;

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};

InParser in("bfs.in");
ofstream out("bfs.out");

pair <int, int> much[1000001];
int last[100001];

int coada[100001], st, dr = -1;
int dist[100001];

int main()
{
    int n, m, s, x, y;
    in >> n >> m >> s;
    for(int i = 1; i <= m; i++)
    {
        in >> x >> y;
        much[i] = {y, last[x]};
        last[x] = i;
    }
    for(int i = 1; i <= n; i++)
        dist[i] = -1;
    dist[s] = 0;
    coada[++dr] = s;
    while(st <= dr)
    {
        int x = coada[st++];
        for(int y = last[x]; y != 0; y = much[y].second)
            if(dist[much[y].first] == -1)
            {
                dist[much[y].first] = dist[x] + 1;
                coada[++dr] = much[y].first;
            }
    }
    for(int i = 1; i <= n; i++)
        out << dist[i] << " ";
    return 0;
}