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最新推荐文章于 2018-07-19 10:35:04 发布

原创最新推荐文章于 2018-07-19 10:35:04 发布 · 1k 阅读

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本文深入探讨了无脑迪杰斯特拉算法的优化策略，并将其应用于稀疏图的处理中，着重强调了邻接表作为最优处理方式的重要性。通过实例解析，详细阐述了算法的实现步骤及效率提升方法。

无脑dijkstra, 转问题为单源再处理(稀疏图用邻接表才是最优处理方式)

#include <stdio.h>
#include <string.h>

int dist[1001];
char k[1001];
int g[1001][1001];

int main()
{
	int t, s, d;
	int a, b, time;
	int i;
	int c;
	int e;
	int next;
	int min_dist;
	
	while (scanf("%d%d%d", &t, &s, &d) != EOF) {
		memset(g, 0, 1001 * 1001 * sizeof(int));
		for (i = 0; i < t; i++) {
			scanf("%d%d%d", &a, &b, &time);
			if (g[a][b] == 0 || g[a][b] > time)
				g[a][b] = g[b][a] = time;
		}
		for (i = 0; i < s; i++) {
			scanf("%d", &c);
			g[0][c] = 1;
		}
		memset(k, 0, 1001 * sizeof(char));
		memset(dist, 0x7f, 1001 * sizeof(int));
		c = 0;
		dist[0] = 0;
		for (;;) {
			k[c] = 1;
			for (i = 1; i < 1001; i++) {
				if (g[c][i] != 0)
					if (dist[c] + g[c][i] < dist[i])
						dist[i] = dist[c] + g[c][i];
			}
			next = 0x7f7f7f7f;
			for (i = 1; i < 1001; i++) {
				if (k[i])
					continue;
				if (dist[i] < next) {
					next = dist[i];
					c = i;
				}
			}
			if (next == 0x7f7f7f7f)
				break;
		}
		min_dist = 0x7f7f7f7f;
		for (i = 0; i < d; i++) {
			scanf("%d", &e);
			if (dist[e] < min_dist)
				min_dist = dist[e];
		}
		printf("%d\n", min_dist - 1);
	}
	return 0;
}