Cod sursa(job #2718443)

Utilizator AndreiAlexandru2k3Ciucan Andrei Alexandru AndreiAlexandru2k3 Data 8 martie 2021 19:08:57
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 3.8 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;
    }
};

class OutParser {
private:
    FILE *fout;
    char *buff;
    int sp;

    void write_ch(char ch) {
        if (sp == 50000) {
            fwrite(buff, 1, 50000, fout);
            sp = 0;
            buff[sp++] = ch;
        } else {
            buff[sp++] = ch;
        }
    }


public:
    OutParser(const char* name) {
        fout = fopen(name, "w");
        buff = new char[50000]();
        sp = 0;
    }
    ~OutParser() {
        fwrite(buff, 1, sp, fout);
        fclose(fout);
    }

    OutParser& operator << (int vu32) {
        if (vu32 <= 9) {
            write_ch(vu32 + '0');
        } else {
            (*this) << (vu32 / 10);
            write_ch(vu32 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (long long vu64) {
        if (vu64 <= 9) {
            write_ch(vu64 + '0');
        } else {
            (*this) << (vu64 / 10);
            write_ch(vu64 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (char ch) {
        write_ch(ch);
        return *this;
    }
    OutParser& operator << (const char *ch) {
        while (*ch) {
            write_ch(*ch);
            ++ch;
        }
        return *this;
    }
};


InParser f("dijkstra.in");
OutParser g("dijkstra.out");

const int NMAX = 50001,
          INF = INT_MAX / 2;

int n, m, vf;
vector <pair<int, int >> G[NMAX];
set<pair<int, int>>Q;
int d[NMAX];

void citire()
{
    f >> n >> m;
    while(m--)
    {
        int x, y, c;
        f >> x >> y >> c;
        G[x].push_back(make_pair(y, c));
    }
}

void Dijkstra(int nod)
{
    for(int i = 1; i <= n; i++)
        d[i] = INF;
    d[nod] = 0;
    Q.insert(make_pair(0, nod));
    while(!Q.empty())
    {
        int nod_curent = Q.begin()->second;
        int dist = Q.begin()->first;
        Q.erase(Q.begin());
        //
        for(auto &x : G[nod_curent])
        {
            int y = x.first;
            int c = x.second;
            if(d[y] > d[nod_curent] + c)
            {
                if(d[y] != INF)
                    Q.erase(Q.find(make_pair(d[y], y)));
                d[y] = d[nod_curent] + c;
                Q.insert(make_pair(d[y], y));
            }
        }
    }
}

void afis()
{
    for(int i = 1; i <= n; i++)
        g << ((d[i] != INF) ? d[i] : -1) << ' ';
}

int main()
{
    citire();
    Dijkstra(1);
    for (int i = 2; i <= n; ++i)
    {
        if (d[i] == INF)
        {
            d[i] = 0;
        }
        g << d[i] << ' ';
    }
    g << '\n';
    return 0;
}