1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
| #include <bits/stdc++.h>
#define N 100010
#define M 300010
using namespace std;
typedef long long ll;
struct Edge {
int to, ne, w;
} edges[M << 1];
int h[N], hs[N], idx = 0;
int scc_cnt = 0, dfs_cnt = 0;
int scc_id[N], scc_size[N];
int dfn[N], low[N];
int dist[N];
stack<int> stk;
bool in_stk[N];
void add(int head[], int a, int b, int w) {
idx++;
edges[idx].to = b;
edges[idx].ne = head[a];
edges[idx].w = w;
head[a] = idx;
}
void tarjan(int u) {
dfn[u] = low[u] = ++dfs_cnt;
stk.push(u);
in_stk[u] = true;
for (int i = h[u]; ~i; i = edges[i].ne) {
int j = edges[i].to;
if (!dfn[j]) {
tarjan(j);
low[u] = min(low[u], low[j]);
} else if (in_stk[j]) {
low[u] = min(low[u], dfn[j]);
}
}
if (dfn[u] == low[u]) {
scc_cnt++;
int t;
do {
t = stk.top();
stk.pop();
in_stk[t] = false;
scc_id[t] = scc_cnt;
scc_size[scc_cnt]++;
} while (t != u);
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
memset(h, -1, sizeof h);
memset(hs, -1, sizeof hs);
int n, m;
cin >> n >> m;
for (int i = 1; i <= n; i++) add(h, 0, i, 1);
while (m--) {
int t, a, b;
cin >> t >> a >> b;
if (t == 1) {
add(h, a, b, 0);
add(h, b, a, 0);
} else if (t == 2) add(h, a, b, 1);
else if (t == 3) add(h, b, a, 0);
else if (t == 4) add(h, b, a, 1);
else add(h, a, b, 0);
}
tarjan(0);
for (int i = 0; i <= n; i++) {
for (int j = h[i]; ~j; j = edges[j].ne) {
int k = edges[j].to;
int a = scc_id[i], b = scc_id[k];
if (a == b) {
if (edges[j].w > 0) {
cout << -1 << endl;
return 0;
}
} else add(hs, a, b, edges[j].w);
}
}
for (int i = scc_cnt; i >= 1; i--) {
for (int j = hs[i]; ~j; j = edges[j].ne) {
int k = edges[j].to;
dist[k] = max(dist[k], dist[i] + edges[j].w);
}
}
ll res = 0;
for (int i = 1; i <= scc_cnt; i++) res += dist[i] * scc_size[i];
cout << res << endl;
return 0;
}
|
