Cod sursa(job #2077997)

Utilizator cojocarugabiReality cojocarugabi Data 28 noiembrie 2017 19:53:19
Problema Arbore partial de cost minim Scor 90
Compilator cpp Status done
Runda Arhiva educationala Marime 3.32 kb
#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define ll long long
#define dbg(v) cerr<<#v<<" = "<<v<<'\n'
#define vi vector<int>
#define vl vector <ll>
#define pii pair<int,int>
#define mp make_pair
#define db long double
#define pb push_back
#define all(s) s.begin(),s.end()
template < class T > T smin(T &a,T b) {if (a > b) a = b;return a;}
template < class T > T smax(T &a,T b) {if (a < b) a = b;return a;}
const int N = (int)(2e5) + 5;
vector < pii > g[N];
int f[N];
int get(int k)
{
    return k == f[k] ? k : f[k] = get(f[k]);
}
pair < int , pii > dp[N];
inline int readChar();
template <class T = int> inline T readInt();
template <class T> inline void writeInt( T x, char end = 0 );
inline void writeChar( int x );
inline void writeWord( const char *s );

/** Read */

static const int buf_size = 4096;

inline int getChar() {
    static char buf[buf_size];
    static int len = 0, pos = 0;
    if (pos == len)
        pos = 0, len = fread(buf, 1, buf_size, stdin);
    if (pos == len)
        return -1;
    return buf[pos++];
}

inline int readChar() {
    int c = getChar();
    while (c <= 32)
        c = getChar();
    return c;
}

template <class T>
inline T readInt() {
    int s = 1, c = readChar();
    T x = 0;
    if (c == '-')
        s = -1, c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return s == 1 ? x : -x;
}

/** Write */

static int write_pos = 0;
static char write_buf[buf_size];

inline void writeChar( int x ) {
    if (write_pos == buf_size)
        fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
    write_buf[write_pos++] = x;
}

template <class T>
inline void writeInt( T x, char end ) {
    if (x < 0)
        writeChar('-'), x = -x;

    char s[24];
    int n = 0;
    while (x || !n)
        s[n++] = '0' + x % 10, x /= 10;
    while (n--)
        writeChar(s[n]);
    if (end)
        writeChar(end);
}

inline void writeWord( const char *s ) {
    while (*s)
        writeChar(*s++);
}

struct Flusher {
    ~Flusher() {
        if (write_pos)
            fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
    }
} flusher;
int main(void)
{
    freopen("apm.in","r",stdin);
    freopen("apm.out","w",stdout);
    int n,m;
    n = readInt();
    m = readInt();
    for (int i = 1;i <= n;++i)
        f[i] = i;
    while (m --)
    {
        int a,b,c;
        a = readInt();
        b = readInt();
        c = readInt();
        g[a].pb(mp(c,b));
        g[b].pb(mp(c,a));
    }
    vector < pii > ans;
    ll answer = 0;
    while (*min_element(f + 1,f + 1 + n) != *max_element(f + 1,f + 1 + n))
    {
        for (int i = 1;i <= n;++i)
            dp[i] = mp((int)(1e9),mp(-1,-1));
        for (int i = 1;i <= n;++i)
            for (auto it : g[i])
                if (get(i) != get(it.se))
                    smin(dp[get(i)],mp(it.fi,mp(it.se,i)));
        for (int i = 1;i <= n;++i)
            if (i == get(i))
            {
                if (i != get(dp[i].se.fi))
                    answer += dp[i].fi,ans.pb(dp[i].se),f[get(dp[i].se.fi)] = i;
            }
        for (int i = 1;i <= n;++i)
            f[i] = get(i);
    }
    writeInt(answer,'\n');
    writeInt(n - 1,'\n');
    for (auto it : ans)
        writeInt(it.fi,' '),writeInt(it.se,'\n');
    return 0;
}