java 迪杰斯特拉算法优先队列 迪杰斯特拉算法的优化 题目 给定一个n个点m条边的有向图,图中可能存在重边和自环,所有边权均为非负值。 请你求出1号点到n号点的最短距离,如果无法从1号点走到n号点,则输出-1。 输入格式 第一行包含整数n和m。 接下来m行每行包含三个整数x,y,z,表示存在一条从点x到点y的有向边,边长为z
优先队列下的迪杰斯特拉算法 首先由于加入到队列中的数据的值将不能改变,而有些点的最短距离更新时,还留在队列中的该点仍是该点更新之前的值,而此时的值已经成为了垃圾值(因为它已经不是该点的最短距离了,弹出之后更新的周围的点也不是最短距离)所以对于某些最短距离已经更新的点,再使用更新之前的点的值进行...
Nextmlines contain the roads. Each road is given as a group of three integersai, bi, li(1 ≤ ai, bi ≤ n;ai ≠ bi; 1 ≤ li ≤ 106) — the cities that are connected by thei-th road and the time needed to ride along it. The road is directed fr...
Nextmlines contain the roads. Each road is given as a group of three integersai, bi, li(1 ≤ ai, bi ≤ n;ai ≠ bi; 1 ≤ li ≤ 106) — the cities that are connected by thei-th road and the time needed to ride along it. The road is directed fr...