1 #include<algorithm> //SPFA
2 #include<queue>
3 #include<stdio.h>
4 #include<string.h>
5 #include<vector>
6 using namespace std;
7
8 const int maxn = 105;
9 const int INF = 0xfffffff;
10
11 struct node
12 {
13 int y, time;
14 node(int y, int t):y(y), time(t){}
15 };
16 vector<node> G[maxn]; //G[i][j] 从i到G[i][j].y 的时间为G[i][j].time
17 int v[maxn];
18
19 void spfa(int s)
20 {
21 queue<int> Q;
22 Q.push(s);
23
24 while(Q.size())
25 {
26 s = Q.front();Q.pop();
27 int len = G[s].size();
28
29 for(int i=0; i<len; i++)
30 {
31 node q = G[s][i];
32 if(v[q.y] > v[s]+q.time)
33 {
34 v[q.y] = v[s] + q.time;
35 Q.push(q.y);
36 }
37 }
38 }
39 }
40
41 int main()
42 {
43 int N;
44
45 while(scanf("%d", &N) != EOF)
46 {
47 int i, j, x;
48 char s[30];
49
50 for(i=1; i<=N; i++)
51 {
52 v[i] = INF;
53 G[i].clear();
54 }
55 v[1] = 0;
56
57 for(i=2; i<=N; i++)
58 for(j=1; j<i; j++)
59 {
60 scanf("%s", s);
61 if(s[0] != 'x')
62 {
63 sscanf(s, "%d", &x);
64 G[i].push_back(node(j, x));
65 G[j].push_back(node(i, x));
66 }
67 }
68
69 spfa(1);
70
71 int ans = -INF;
72
73 for(i=1; i<=N; i++)
74 ans = max(ans, v[i]);
75
76 printf("%d\n", ans);
77 }
78
79 return 0;
80 }
