HDU T2544 最短路

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                                    HDU T2544 最短路

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题目思路：

    模板裸题......

 

Spfa写法：

#include<cstdio>
#include<queue> 
#include<cstring>
#define maxm 10005
#define maxn 105
#define INF 0x3f3f3f3f
using namespace std;

struct Edge{
	int to,cost,next;
}edge[maxm];

bool vis[maxn];
int dis[maxn],head[maxn],n,m,cnt;

void Init(){
	memset(vis,false,sizeof(vis));
	memset(head,-1,sizeof(head));
	cnt = 0;
	for(int i=1; i<=n; i++)
	    dis[i] = (i==1)? 0 : INF;
}

void add(int from,int to,int cost){
	edge[cnt].to = to;
	edge[cnt].cost = cost;
	edge[cnt].next = head[from];
	head[from] = cnt++;
}

void Spfa(int s){
	int u;
	queue<int> Q;
	Q.push(s);
	dis[s] = 0;
	vis[s] = true;
	while(!Q.empty()){
		u = Q.front();
		Q.pop();
		vis[u] = false;
		for(int i=head[u]; i!=-1; i=edge[i].next){
			int v = edge[i].to;
			int w = edge[i].cost;
			if(dis[v] > dis[u] + w){
				dis[v] = dis[u] + w;
				if(!vis[v]){
					vis[v] = true;
					Q.push(v);
				}
			} 
		}
	}
}

int main(){
	int u,v,w;
	while(scanf("%d%d",&n,&m),n+m){
		Init();
		for(int i = 0;i < m; i++){
			scanf("%d%d%d",&u,&v,&w);
			add(u,v,w);
			add(v,u,w);
		}
		Spfa(1);
		printf("%d\n",dis[n]);
	}
	return 0;
}

 

 

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Floyd写法

#include<cstdio>
#include<algorithm>
#define INF 0x3f3f3f3f
#define maxn 105
using namespace std;
int map[maxn][maxn],n,m;

void Init(){
	for(int i = 0; i <= n; i++)
	    for(int j = 0; j <= n ;j++){
	    	if(i == j) map[i][j] = 0; //floyd算法，要将对角线初始化为0！！！！ 
	    	else map[i][j] = INF;     //例：k==1，i=j==3; 
	    }
} 

void Floyd(){
	for(int k = 1; k <= n; k++)
	    for(int i = 1; i <= n; i++)
	        for(int j = 1; j <= n; j++)
	            map[i][j] = min(map[i][j],map[i][k]+map[k][j]); 
}

int main(){
	int a,b,c;
	while(~scanf("%d%d",&n,&m),n+m)
	{
		Init();
		for(int i = 0; i < m; i++){
			scanf("%d%d%d",&a,&b,&c);
			map[a][b] = map[b][a] = min(map[a][b],c);
		}
		Floyd();
		printf("%d\n",map[1][n]); 
	}
	return 0;
}