貌似百度没题解
贪心是贪不过的，举个例子
5 4 10
1 2 2
2 4 3
3 4 2
4 5 3
还有注意不连通情况
1 #include<iostream>
2 #include<sstream>
3 #include<cstdio>
4 #include<cstdlib>
5 #include<string>
6 #include<cstring>
7 #include<algorithm>
8 #include<functional>
9 #include<iomanip>
10 #include<numeric>
11 #include<cmath>
12 #include<queue>
13 #include<vector>
14 #include<set>
15 #include<map>
16 #include<cctype>
17 const double PI = acos(-1.0);
18 const int INF = 0x3f3f3f3f;
19 const int NINF = -INF - 1;
20 const int maxn = 1e5 + 5;
21 typedef long long ll;
22 #define MOD 1000000007
23 using namespace std;
24 int n, m, st;
25 int vis[maxn];
26 int rec = 0;
27 typedef pair<int, int> P;
28 struct node
29 {
30 int next, cost;
31 int flag;
32 };
33 vector<node> G[maxn];
34 void bfs()
35 {
36 queue<P> q;
37 q.push(P(1, st));
38 while(q.size())
39 {
40 P p = q.front();
41 q.pop();
42 for(int i = 0; i < G[p.first].size(); ++i)
43 {
44 node tmp = G[p.first][i];
45 int mp;
46 if(!tmp.flag) mp = p.second - tmp.cost;
47 else mp = p.second + tmp.cost;
48 if (vis[tmp.next] == -1) {
49 vis[tmp.next] = mp;
50 q.push(P(tmp.next, vis[tmp.next]));
51 }
52 else{
53 if(vis[tmp.next] != mp) {
54 rec = 1;
55 break;
56 }
57 }
58 }
59 if(rec) break;
60 }
61 }
62 int main()
63 {
64 memset(vis, -1, sizeof(vis));
65 scanf("%d %d %d", &n, &m, &st);
66 for(int i = 0; i < m; ++i)
67 {
68 int x, y, w;
69 scanf("%d %d %d", &x, &y, &w);
70 G[x].push_back(node{y, w, 0});
71 G[y].push_back(node{x, w, 1});
72 }
73 vis[1] = st;
74 bfs();
75 for(int i = 1; i <= n; ++i)
76 {
77 if(vis[i] == -1)
78 {
79 rec = 1;
80 break;
81 }
82 }
83 if(rec)
84 {
85 cout << "QAQ";
86 }
87 else
88 {
89 cout << "QWQ" << endl;
90 for(int i = 1; i <= n; ++i)
91 {
92 cout << vis[i] << endl;
93 }
94 }
95 return 0;
96 }