题目链接
题目要求分别以dfs和bfs遍历图，并且要满足字典序最小。
题目难度不大，但是要满足字典序最小，貌似用链式前向星写不了。改成vector用sort就可以过了。
AC代码：
/* * @Author: hesorchen * @Date: 2020-07-03 17:05:01 * @LastEditTime: 2020-09-02 21:40:38 * @Description: https://hesorchen.github.io/ */ #include <map> #include <set> #include <list> #include <queue> #include <deque> #include <cmath> #include <stack> #include <vector> #include <bitset> #include <cstdio> #include <string> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> using namespace std; #define endl '\n' #define PI acos(-1) #define PB push_back #define ll long long #define INF 0x3f3f3f3f #define mod 1000000007 #define pll pair<ll, ll> #define lowbit(abcd) (abcd & (-abcd)) #define max(a, b) ((a > b) ? (a) : (b)) #define min(a, b) ((a < b) ? (a) : (b)) #define IOS \ ios::sync_with_stdio(false); \ cin.tie(0); \ cout.tie(0); #define FRE \ { \ freopen("in.txt", "r", stdin); \ freopen("out.txt", "w", stdout); \ } inline int read() { int x = 0, f = 1; char ch = getchar(); while (ch < '0' || ch > '9') { if (ch == '-') f = -1; ch = getchar(); } while (ch >= '0' && ch <= '9') { x = (x << 1) + (x << 3) + (ch ^ 48); ch = getchar(); } return x * f; } //head============================================================================== long long ct = 1, ansdfsct, ansbfsct; vector<long long> vec[100010]; long long visdfs[100010]; long long ansdfs[100010]; long long visbfs[100010]; long long ansbfs[100010]; void dfs(long long now) { long long sum = vec[now].size(); for (int i = 0; i < sum; i++) { long long v = vec[now][i]; if (!visdfs[v]) { visdfs[v] = 1; ansdfs[ansdfsct++] = v; dfs(v); } } } queue<long long> q; void bfs(long long s) { q.push(s); while (q.size()) { long long now = q.front(); q.pop(); long long sum = vec[now].size(); for (int i = 0; i < sum; i++) { long long v = vec[now][i]; if (!visbfs[v]) { visbfs[v] = 1; ansbfs[ansbfsct++] = v; q.push(v); } } } } int main() { long long n, m; visdfs[1] = visbfs[1] = 1; scanf("%lld %lld", &n, &m); for (int i = 1; i <= m; i++) { long long u, v; scanf("%lld %lld", &u, &v); vec[u].push_back(v); } for (int i = 1; i <= n; i++) sort(vec[i].begin(), vec[i].end()); dfs(1); printf("1 "); for (int i = 0; i < ansdfsct; i++) printf("%lld ", ansdfs[i]); printf(" \n"); bfs(1); printf("1 "); for (int i = 0; i < ansbfsct; i++) printf("%lld ", ansbfs[i]); return 0; } /* */