HDU 2680 Choose the best route (SPFA algorithm)

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The main idea:

Enter N,m,s, which represents n points, m edges, and s represents the end point. Then input the side, each side input p,q,t;p,q represents two points, T is the edge right, notice that the topic is from P point to Q side, it should establish a directed graph. Then enter W to indicate that there is a W starting point, and then enter the starting point, and for multiple starting points, if you use a SPFA for each starting point, then the starting point can be a bit cumbersome, so you might want to do this: In addition to a point that does not coincide with the topic, set the Benquan of all the starting point to 0, Then finding the point as the starting point is the shortest. Please refer to the code for details:

#include <stdio.h> #include <string.h> #include <queue> #define MAXN 1010#define MAXM 40040#define INF 0x3f3f3f3fusing namespace Std;int head[maxn];int dis[maxn];int mark[maxn];struct node{int from,to,val,next;}; Node Edge[maxm];int num,n,m,s;void getmap (int u,int v,int W) {node e={u,v,w,head[u]};edge[num]=e;head[u]=num++;} void SPFA (int s) {Queue<int>q;memset (mark,0,sizeof (Mark)); memset (dis,inf,sizeof (dis)); Q.push (s); mark[s]=1; Dis[s]=0;while (!q.empty ()) {int Top=q.front (); Q.pop (); mark[top]=0;for (int i=head[top];i!=-1;i=edge[i].next) {int u= Edge[i].to;if (dis[u]>dis[top]+edge[i].val) {dis[u]=dis[top]+edge[i].val;if (!mark[u]) {mark[u]=1;q.push (U);}}}} int main () {while (scanf ("%d%d%d", &n,&m,&s)!=eof) {memset (head,-1,sizeof (head)); num=0;for (int i=0;i< m;i++) {int a,b,d;scanf ("%d%d%d", &a,&b,&d); Getmap (a,b,d);} int w,start;scanf ("%d", &w), for (int i=0;i<w;i++) {scanf ("%d", &start); Getmap (0,start,0);} SPFA (0); if (dis[s]==inf) printf (" -1\n"); elseprintf ("%D\n ", Dis[s]);} return 0;}

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HDU 2680 Choose the best route (SPFA algorithm)