蛇皮法spfa全部TLE啦，求优化

#include <iostream>
#include <queue>
#include <cstring>
using namespace std;

const int N = (int)1e6;
int total_area, total_road, start_area;
struct road {
	int start;
	int end;
	int scale;
}roads[N];
bool state[N];
int dist[N];
queue <int> line;
int main() {
	cin >> total_area >> total_road >> start_area;
	memset(dist,0x3f3f3f3f,sizeof(dist));
	dist[start_area] = 0;
	for (int i = 1; i <= total_road; i++) {
		int a, b, c;
		cin >> a >> b >> c;
		roads[i].start = a;
		roads[i].end = b;
		roads[i].scale = c;
	}
	line.push(start_area);
	state[start_area] = 1;
	while (line.size()) {
		int origin = line.front();
		line.pop();
		state[origin] = 0;
		for (int i = 1; i <= total_road; i++) {
			if (roads[i].start == origin) {
				int a = roads[i].start;
				int b = roads[i].end;
				int c = roads[i].scale;
				if (dist[a] + c < dist[b]) {
					dist[b] = dist[a] + c;
				}
			}
		}
		for (int i = 1; i <= total_road; i++) {
			if (roads[i].start == origin && state[roads[i].end] == 0) {
				line.push(roads[i].end);
				state[roads[i].end] = 1;
			}
		}
	}
	for (int i = 1; i <= total_area; i++) {
		cout << dist[i] << " ";
	}
	return 0;
}