拓扑排序精讲
拓扑排序看上去很复杂，其实了解其原理之后，代码不难
代码随想录
import java.util.*;public class Main{public static void main (String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();int m = sc.nextInt();List<List<Integer>> last = new ArrayList<>();for(int i = 0; i < n; i++){last.add(new ArrayList<>());}int[] inDegree = new int[n];for(int i = 0; i < m; i++){int star = sc.nextInt();int end = sc.nextInt();inDegree[end]++;last.get(star).add(end);}Deque<Integer> queue = new ArrayDeque<>();List<Integer> result = new ArrayList<>();for(int i = 0; i < inDegree.length; i++){if(inDegree[i] == 0){queue.add(i);//result.add(i);}}while(!queue.isEmpty()){int cur = queue.remove();result.add(cur);if(last.get(cur).
