A1018 Public Bike Management [dj]

#include<iostream>
#include<vector>
#include<queue>
#include<stack>
#include<string>
#include<math.h>
#include<algorithm>
#include<map>
#include<cstring>
#include<set>
using namespace std;
const int maxn = 501;
const int inf = 10000000;
int d[maxn], minneed = inf, minback = inf;
int cp, n,qs,m;
bool vis[maxn] = { false };	
int G[maxn][maxn], weight[maxn];
vector<int>pre[maxn];
vector<int>tempPath, path;

void djs(int s)
{
	fill(d, d + maxn, inf);
	d[s] = 0;
	for (int i = 0; i <= n; i++)
	{
		int u = -1, mins = inf;
		for (int j = 0; j <= n; j++)
		{
			if (vis[j] == false && d[j] < mins)
			{
				u = j;
				mins = d[j];
			}
		}
		if (u == -1) return;

		vis[u] = true;
		for (int v = 0; v <= n; v++)
		{
			if (vis[v] == false && G[u][v] != inf)
			{
				if (d[u] + G[u][v] < d[v])
				{
					d[v] = d[u] + G[u][v];
					pre[v].clear();
					pre[v].push_back(u);
				}
				else if (d[u] + G[u][v] == d[v])
				{
					pre[v].push_back(u);
				}
			}
		}
	}
}
void dfs(int v)
{
	if (v == 0)
	{
		tempPath.push_back(v);
		int need = 0, back = 0;
		for (int i = tempPath.size() - 1; i >= 0; i--)
		{
			int id = tempPath[i];
			if (weight[id] > 0)
			{
				back += weight[id];
			}
			else
			{
				if (back > abs(weight[id]))
				{
					back -= abs(weight[id]);
				}
				else
				{
					need += abs(weight[id]) - back;
					back = 0;
				}
			}
		}
		if (need < minneed)
		{
			minneed = need;
			minback = back;
			path = tempPath;
		}
		else if (need == minneed && back < minback)
		{
			minback = back;
			path = tempPath;
		}
		tempPath.pop_back();
		return;
	}
	tempPath.push_back(v);
	for (int i = 0; i < pre[v].size(); i++)
	{
		dfs(pre[v][i]);
	}	
	tempPath.pop_back();
}	

int main()
{
	cin>>cp>>n>>qs>> m;
	int u, v;
	fill(G[0], G[0] + maxn * maxn, inf);
	for (int i = 1; i <= n; i++)
	{
		cin >> weight[i];
		weight[i] -= cp / 2;
	}
	for (int i = 0; i < m; i++)
	{
		cin >> u >> v;
		cin >> G[u][v];
		G[v][u] = G[u][v];
	}
	djs(0);
	dfs(qs);
	cout << minneed << " ";
	for (int i = path.size() - 1;i >= 0; i--)
	{
		cout << path[i];
		if (i > 0) cout << "->";
	}
	cout << " " << minback << endl;
	return 0;
}