标签：图论   spfa   算法   

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2112

HDU Today

6
xiasha westlake
xiasha station 60
xiasha ShoppingCenterofHangZhou 30
station westlake 20
ShoppingCenterofHangZhou supermarket 10
xiasha supermarket 50
supermarket westlake 10
-1

50


Hint:
The best route is:
xiasha->ShoppingCenterofHangZhou->supermarket->westlake

真是醉了的题目，错了n次，有题意理解错误，数组开小错误等等，，不忍直视了

贴一个用map做的吧

【源代码】

#include <cstdio>
#include <queue>
#include <string>
#include <cstring>
#include <iostream>
#include <vector>
#include <map>
using namespace std;
const int maxn = 155;
const int maxe = 155;
const int INF = 0xfffffff;
int n,cnt;
int minDist[maxn];
bool inqueue[maxn];
int head[maxn];int edgeNum=0;
struct node{
	int to,len,next;
	 node(int to=0,int len=0):to(to),len(len){}
}edge[20005]; //开10010就re了 
void addEdge(int a,int b,int len){
	edge[edgeNum].to=b;
	edge[edgeNum].len=len;
	edge[edgeNum].next=head[a];
	head[a]=edgeNum++;
}
void init(){
	memset(head,-1,sizeof(head));
	edgeNum=0;
}
int SPFA(){
	for(int i=1;i<=cnt;i++){
		minDist[i]=INF;
		inqueue[i]=0;
	}
	queue<int>Q;
	inqueue[1]=1;
	Q.push(1);
	minDist[1]=0;
	while(!Q.empty()){
		int v1 =Q.front();
		Q.pop();
		inqueue[v1]=0;
		for(int i=head[v1];i!=-1;i=edge[i].next){
			int v2=edge[i].to;
			int len=edge[i].len;
			if(minDist[v2]>minDist[v1]+len){
				minDist[v2]=minDist[v1]+len;
				if(!inqueue[v2]){
					inqueue[v2]=1;
					Q.push(v2);
				}
		
			}
		}
	}
	if(minDist[2]>=INF) return -1;
	return minDist[2];
}
int main(){
	map<string,int>mp; //遇到字符串根int匹配的题，果断用map！！
	char st[35],end[35]; char tmp1[35],tmp2[35]; int len;
	while(scanf("%d",&n)!=EOF){
		if(n==-1) break;
		init();	
		mp.clear(); //不要忘了清空
		cnt=0;
		scanf("%s %s",st,end);
		mp[st]=++cnt;
		if(mp[end]==0){ //开头结尾不一样时
			mp[end]=++cnt;
		}	
		for(int i=0;i<n;i++){
			scanf("%s%s%d",tmp1,tmp2,&len);
			if(mp[tmp1]==0) mp[tmp1]=++cnt;
			if(mp[tmp2]==0) mp[tmp2]=++cnt;
			addEdge(mp[tmp1],mp[tmp2],len);
			addEdge(mp[tmp2],mp[tmp1],len);
		}
		if(mp[st]==mp[end]){
			printf("0\n");continue;
		}			
		int ans=SPFA();
			printf("%d\n",ans);
	}
	return 0;
}

HDU 2112 HDU Today(最短路 SPFA)

标签：图论   spfa   算法   

原文地址：http://blog.csdn.net/chaiwenjun000/article/details/47700617