Cod sursa(job #2454966)

Utilizator vladadAndries Vlad Andrei vladad Data 10 septembrie 2019 15:56:04
Problema Algoritmul lui Dijkstra Scor 90
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 2.16 kb
#include<bits/stdc++.h>
#define fi first
#define sc second
using namespace std;

#include <stdio.h>
#include <ctype.h>

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;
	}
} f("dijkstra.in");
ofstream g("dijkstra.out");
int n, m, dis[200001];
vector<pair<int, int>>v[200001];
set<pair<int, int>>s;
bool viz[200001];
void dijkstra(int nod)
{
    viz[nod]=1;
    for(int i=0; i<v[nod].size(); i++)
    {
        if(!viz[v[nod][i].fi])
        {
            viz[v[nod][i].fi]=1;
            s.insert(make_pair(v[nod][i].fi, dis[nod]+v[nod][i].sc));
            dis[v[nod][i].fi]=dis[nod]+v[nod][i].sc;
        }
        else
        {
            if(v[nod][i].sc+dis[nod]<dis[v[nod][i].fi])
            {
                s.erase(make_pair(v[nod][i].fi, dis[v[nod][i].fi]));
                s.insert(make_pair(v[nod][i].fi, dis[nod]+v[nod][i].sc));
                dis[v[nod][i].fi]=dis[nod]+v[nod][i].sc;
            }
        }
    }
}
int main()
{
    f>>n>>m;
    for(int i=1; i<=m; i++)
    {
        int x, y, cost;
        f>>x>>y>>cost;
        v[x].push_back(make_pair(y, cost));
    }
    s.insert(make_pair(1, 0));
    while(!s.empty())
    {
        int x=(*s.begin()).fi;
        s.erase(s.begin());
        dijkstra(x);
    }
    for(int i=2; i<=n; i++)
        g<<dis[i]<<' ';
    return 0;
}