洛谷P1339 [USACO09OCT]热浪Heat Wave
2017-03-18
题目：https://www.luogu.org/problem/show?pid=1339
相当于spfa的入门题了吧。
spfa不会的同学，这个教程不错：http://www.360doc.com/content/13/1208/22/14357424_335569176.shtml
1 #include<iostream> 2 #include<cstdio> 3 #include<algorithm> 4 #include<queue> 5 using namespace std; 6 7 struct node{ 8 int value; 9 int to; 10 node *next; 11 }; 12 13 const int maxn=10000; 14 int t,c,ts,te; 15 int dist[maxn]; 16 int re,rs,ci; 17 node* line[maxn]; 18 queue<int> q; 19 20 void spfa(int src){ 21 node *tmp; 22 int now; 23 q.push(src); 24 dist[src]=0; 25 while (!q.empty()){ 26 now=q.front(); 27 q.pop(); 28 tmp=line[now]->next; 29 while (tmp){ 30 if (dist[tmp->to]>dist[now]+tmp->value){ 31 dist[tmp->to]=dist[now]+tmp->value; 32 q.push(tmp->to); 33 } 34 tmp=tmp->next; 35 } 36 } 37 } 38 39 int main(){ 40 //freopen("heatwave.in","r",stdin); 41 //freopen("heatwave.out","w",stdout); 42 scanf("%d%d%d%d",&t,&c,&ts,&te); 43 node *tmp; 44 for (int i=1;i<=t;++i){ 45 dist[i]=maxn; 46 line[i]=new node; 47 line[i]->next=NULL; 48 } 49 for (int i=1;i<=c;++i){ 50 tmp=new node; 51 scanf("%d%d%d",&rs,&re,&ci); 52 53 tmp->to=re; 54 tmp->value=ci; 55 tmp->next=line[rs]->next; 56 line[rs]->next=tmp; 57 58 59 tmp=new node; 60 tmp->to=rs; 61 tmp->value=ci; 62 tmp->next=line[re]->next; 63 line[re]->next=tmp; 64 } 65 66 spfa(ts); 67 68 cout<<dist[te]; 69 //fclose(stdin); 70 //fclose(stdout); 71 return 0; 72 }
骗分真神奇，暴力出奇迹。
