P10193 [USACO24FEB] Bessla Motors G

**注意：本题的时间限制为 3 秒，通常限制的 1.5 倍。本题的内存限制为 512MB，通常限制的 2 倍。**

****Note: The time limit for this problem is 3s, 1.5x the default. The memory limit for this problem is 512MB, twice the default.**** Farmer John would like to promote his line of Bessla electric tractors by showcasing Bessla's network of charging stations. He has identified $N$ ($2\le N\le 5\cdot 10^4$) points of interest labeled $1\dots N$, of which the first $C$ ($1\le C < N$) are charging stations and the remainder are travel destinations. These points of interest are interconnected by $M$ ($1\le M\le 10^5$) bidirectional roads, the $i$-th of which connects distinct points $u_i$ and $v_i$ ($1\le u_i, v_i\le N$) and has length $\ell_i$ miles ($1\le\ell_i\le 10^9$). A Bessla can travel up to $2R$ miles ($1\le R\le 10^9$) on a single charge, allowing it to reach any destination within $R$ miles of a charging station. A destination is deemed _well-connected_ if it is reachable from at least $K$ ($1\le K\le 10$) distinct charging stations. Your task is to assist Farmer John in identifying the set of well-connected travel destinations.

The first line contains five space-separated integers $N$, $M$, $C$, $R$, and $K$. Each of the following $M$ lines contains three space-separated integers $u_i$, $v_i$, and $\ell_i$ such that $u_i\neq v_i$. The charging stations are labeled $1, 2, \ldots, C$. The remaining points of interest are all travel destinations.

First, output the number of well-connected travel destinations on a single line. Then, list all well-connected travel destinations in ascending order, each on a separate line.

##### For Sample 1: We have one charging station at $1$. From this charging station, we can reach point $2$ (since it is distance $3$ away from $1$), but not point $3$ (since it is distance $5$ away from $1$). Thus, only point $2$ is well-connected. ##### For Sample 2: We have charging stations at $1$ and $2$, and both points $3$ and $4$ are within distance $101$ of both $1$ and $2$. Thus, both points $3$ and $4$ are well-connected. #### SCORING: - Inputs 4 and 5: $K = 2$ and $N \le 500$ and $M\le 1000$. - Inputs 6 and 7: $K = 2$. - Inputs 8-15: No additional constraints.