G - MPI Maelstrom

 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 }