dijkstra

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <set>
#include <queue>
#include <map>
#include <sstream>
#include <cstdio>
#include <cstring>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <deque>
#include <bitset>
#include <cassert>
//#include <unordered_set>
//#include <unordered_map>
#define ll              long long
#define pii             pair<int, int>
#define rep(i,a,b)      for(int  i=a;i<=b;i++)
#define dec(i,a,b)      for(int  i=a;i>=b;i--)
#define forn(i, n)      for(int i = 0; i < int(n); i++)
using namespace std;
int dir[4][2] = { { 1,0 },{ 0,1 } ,{ 0,-1 },{ -1,0 } };
const long long INF = 0x7f7f7f7f7f7f7f7f;
const int inf = 0x3f3f3f3f;
const double pi = acos(-1.0);
const double eps = 1e-6;
const ll mod = 1e9+7;

inline ll read()
{
    ll x = 0; bool f = true; char c = getchar();
    while (c < '0' || c > '9') { if (c == '-') f = false; c = getchar(); }
    while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
    return f ? x : -x;
}

ll gcd(ll m, ll n)
{
    return n == 0 ? m : gcd(n, m % n);
}
ll qpow(ll m, ll k)
{
    ll res = 1, t = m;
    while (k)
    {
        if (k & 1)
            res = res * t % mod;
        t = t * t % mod;
        k >>= 1;
    }
    return res;
}
/**********************************************************/

const int N = 2e5 + 5;

struct edge {
    int to, dis, next;
};

edge e[N];
int head[N], dis[N], cnt;
bool vis[N];
int n, m, s;

void add(int u, int v, int w)
{
    cnt++;
    e[cnt].dis = w;
    e[cnt].to = v;
    e[cnt].next = head[u];
    head[u] = cnt;
}

struct node
{
    int dis;
    int pos;
    bool operator < (const node& x)const
    {
        return x.dis < dis;
    }
};

priority_queue<node> q;

void dijkstra()
{
    dis[s] = 0;
    q.push({ 0, s });
    while (!q.empty())
    {
        node f = q.top();
        q.pop();
        int x = f.pos, d = f.dis;
        if (vis[x])
            continue;
        vis[x] = 1;
        for (int i = head[x]; i; i = e[i].next)
        {
            int to = e[i].to;
            if (dis[to] > dis[x] + e[i].dis)
            {
                dis[to] = dis[x] + e[i].dis;
                if (!vis[to])
                {
                    q.push({ dis[to],to });
                }
            }
        }
    }
}

int main()
{
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    cin >> n >> m >> s;
    memset(dis, inf, sizeof(dis));
    rep(i, 1, m)
    {
        int u, v, d;
        cin >> u >> v >> d;
        add(u, v, d);
    }
    dijkstra();
    rep(i, 1, n)
        cout << dis[i] << " ";
    return 0;
}
原文地址:https://www.cnblogs.com/dealer/p/13809860.html