2019ICPC银川站 H. Delivery Route HYSBZ - 2200 道路和航线 dijkstra + 拓扑排序

#include<iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<stack>
#include<cstring>
#include<set>
#include<iterator>
#include<list>
#include<deque>
#include<queue>
#include<map>
#include<cmath>
#include<sstream>
#include<cstdio>
#include<ctime>
#include<iomanip>
//#include<unordered_set>
using namespace std;
#define lowbit(x) x&(-x)
typedef long long ll;
typedef pair<int, int> P;
const int N = 2.5e4 + 10;
const int M = 1.5e5 + 10;
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;
int tot = 0;
int dist[N], bel[N];
int head[N], ver[M], edge[M], Next[M], deg[N];
vector<int>  block[N];
void addedge(int x, int y, int z)
{
	ver[++tot] = y, edge[tot] = z, Next[tot] = head[x], head[x] = tot;
}
int cnt = 0;
void dfs(int s)
{
	block[cnt].push_back(s);
	bel[s] = cnt;
	for (int i = head[s]; i; i = Next[i])
	{	
		if (!bel[ver[i]])
		{
			dfs(ver[i]);
		}
	}
}
queue<int> q; 
priority_queue<P,vector<P>, greater<P> > que;
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	memset(dist, 0x7f, sizeof(dist));
	int t, r, p, s;
	cin >> t >> r >> p >> s;
	while (r--)
	{
		int x, y, z;
		cin >> x >> y >> z;
		addedge(x, y, z);
		addedge(y, x, z);
	}
	for (int i = 1; i <= t; i++)
	{
		if (!bel[i])
		{
			cnt++;
			dfs(i);
		}
	}
	while (p--)
	{
		int x, y, z;
		cin >> x >> y >> z;
		addedge(x, y, z);
		deg[bel[y]]++;
	}
	dist[s] = 0;
	for (int i = 1; i <= cnt; i++)
	{
		if (deg[i] == 0)
			q.push(i);
	}
	while (!q.empty())
	{
		int t = q.front();
		q.pop();
		for (int i = 0; i < block[t].size(); i++)
			que.push(P(dist[block[t][i]], block[t][i]));
		while (!que.empty())
		{
			P p = que.top();
			int u = p.second;
			que.pop();
			if (dist[u] < p.first)
				continue;
			for (int i = head[u]; i; i = Next[i])
			{
				int v = ver[i];
				if (dist[v] > dist[u] + edge[i])
				{
					dist[v] = dist[u] + edge[i];
					if (bel[u] == bel[v])
					{
						que.push(P(dist[v], v));
					}
				}
				if(bel[v] != bel[u])
				{
					deg[bel[v]]--;
					if (deg[bel[v]] == 0)
					{
						q.push(bel[v]);
					}
				}
			}
		}
	}
	for (int i = 1; i <= t; i++)
	{
		if (dist[i] > inf)
		{
			cout << "NO PATH\n";
		}
		else
		{
			cout << dist[i] << "\n";
		}
	}
	return 0;
}