HDU 5137 Shortest Path maximization

http://acm.hdu.edu.cn/showproblem.php?pid=5137

Rt

N is only 30, using SPFA to traverse each of the point methods to find the maximum value

<span style= "FONT-SIZE:14PX;" > #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include < string> #include <queue> #include <map> #include <iostream> #include <sstream> #include < algorithm>using namespace std; #define RD (x) scanf ("%d", &x) #define RD2 (x, y) scanf ("%d%d", &x,&y) #define RD3 (x, Y, z) scanf ("%d%d%d", &x,&y,&z) #define CLR0 (x) memset (x,0,sizeof (×)) #define CLR1 (x) memset (X,-1, sizeof (x)) #define EPS 1e-9const double pi = ACOs ( -1.0); typedef long long ll;const int inf = 1000000000;const int MAXN = 10 05;struct edge{int v,next,c;}    E[maxn<<1];int n,m,head[40],ecnt;bool vis[40];void Add (int u,int v,int c) {e[ecnt] = (edge) {v,head[u],c};    Head[u] = ecnt++;    E[ECNT] = (edge) {u,head[v],c}; HEAD[V] = ecnt++;}    int dis[40];void SPFA () {for (int i = 1;i <= n;++i) dis[i] = inf;    Dis[1] = 0;    Clr0 (VIS);    Queue<int> Q;    Q.push (1); vis[1] = 1; while (!q.emPty ()) {int u = q.front (); Q.pop ();        Vis[u] = false;            for (int i = head[u];i! = -1;i = e[i].next) {int v = E[I].V;                if (Dis[v] > Dis[u] + e[i].c) {Dis[v] = Dis[u] + e[i].c;                    if (!vis[v]) {vis[v] = 1;                Q.push (v);    }}}}}int u[maxn],v[maxn],c[maxn],mx = 0;int mp[40][40];void work () {CLR0 (MP);    mx = 0;        for (int i = 0;i < M;++i) {RD3 (u[i],v[i],c[i]);    Mp[u[i]][v[i]] = mp[u[i]][v[i]] = c[i];        } for (int i = 2;i < N;++i) {CLR1 (head);        ecnt = 0;            for (int j = 0;j < M;++j) {if (i = = U[j] | | i = v[j]) continue;        Add (U[j],v[j],c[j]);  }//for (int j = 1;j <= n;++j)//for (int k = 1;k <= n;++k) {//if (i = = J | | i = = k | |    !MP[J][K]//continue;//Add (J,k,mp[j][k]);/} SPFA ();    MX = max (mx,dis[n]);    } if (mx = = inf) puts ("INF"); else printf ("%d\n", MX);}    int main () {//int _,cas = 1;//RD (_),//while (_--) {//printf ("Case #%d:%i64d\n", cas++,work ());/}    while (RD2 (n,m), n|m) {work (); } return 0;} /**/</span>

HDU 5137 Shortest Path maximization