Ultraviolet A 280-vertex

Question: Count the points in a directed graph that the given starting point cannot reach.

Analysis: Graph Theory and search. You can directly traverse through DFS.

Note: the start point is a point not traversed. initialize the data.

#include <iostream>#include <cstdlib>#include <cstring>#include <cstdio>using namespace std;int maps[110][110];int used[110];void dfs(int s, int n){for (int i = 1 ; i <= n ; ++ i)if (!used[i] && maps[s][i]) {used[i] = 1;dfs(i, n);}}int main(){int n,m,a,b,s;while (~scanf("%d",&n) && n) {memset(maps, 0, sizeof(maps));while (~scanf("%d",&a) && a) while (~scanf("%d",&b) && b)maps[a][b] = 1;scanf("%d",&m);for (int i = 0 ; i < m ; ++ i) {memset(used, 0, sizeof(used));scanf("%d",&s);dfs(s, n);int count = n;for (int j = 1 ; j <= n ; ++ j)count -= used[j];printf("%d",count);for (int j = 1 ; j <= n ; ++ j)if (!used[j])printf(" %d",j);printf("\n");}}return 0;}

Ultraviolet A 280-vertex