【hdu 2112】 HDU Today （ 最短路 Dijkstra）（map）
http://acm.hdu.edu.cn/showproblem.php?pid=2112
这道题给了一个将字符串与int对应的思路，就是使用map
这道题答案对了，但是没有AC，我也不知道为什么。。
1 #include <iostream> 2 #include <cstdio> 3 #include <string> 4 #include <queue> 5 #include <vector> 6 #include <map> 7 using namespace std; 8 const int Ni = 10000; 9 const int INF = 1<<27; 10 11 typedef pair<int,int> pa; 12 13 int dis[Ni],n;//dis使用1~n的部分 14 15 vector<pair<int,int> > eg[Ni]; 16 17 void Dijkstra(int s) 18 { 19 int i,j; 20 cout<<n<<endl; 21 for(i=0;i<=n;i++)//要到n 22 dis[i] = INF; 23 24 priority_queue<pa>q; //优先级队列：小顶堆 25 dis[s] = 0; 26 q.push(make_pair(s,dis[s])); 27 while(!q.empty()) 28 { 29 pa x = q.top(); 30 q.pop(); 31 int w = x.first; 32 for(j = 0;j<eg[w].size();j++)//遍历x的所有邻接点 33 { 34 pa y = eg[w][j];//y是x的邻接点 35 int u = y.first; 36 if(dis[u]>x.second+y.second) 37 { 38 dis[u] = x.second+y.second; 39 q.push(make_pair(u,dis[u])); 40 } 41 } 42 } 43 44 } 45 46 47 int main() 48 { 49 int m,d;//关系个数 50 string a,b; 51 map<string,int> mp; 52 while(cin>>n && n!=-1) 53 { 54 mp.clear(); 55 for(int i = 0;i<=n;i++) 56 eg[i].clear();//初始化 57 cin>>a>>b; 58 bool flag = false; 59 if(a==b) 60 flag = true; 61 mp[a] = 1; 62 mp[b] = 2; 63 int k = 3; 64 int w,u; 65 int t = n; 66 while(t--) 67 { 68 cin>>a>>b>>d; 69 if(!mp[a]) 70 { 71 w = k; 72 mp[a] = k++; 73 } 74 if(!mp[b]) 75 { 76 u = k; 77 mp[b] = k++; 78 } 79 eg[mp[a]].push_back(make_pair(mp[b],d)); 80 eg[mp[b]].push_back(make_pair(mp[a],d)); 81 } 82 if(flag) 83 { 84 cout<<"0\n"; 85 continue; 86 } 87 Dijkstra(1); 88 if(dis[2]!=INF) 89 cout<<dis[2]<<endl; 90 else 91 cout<<"-1\n"; 92 } 93 94 return 0; 95 }
第二次写，依旧WA
1 #include <cstdio> 2 #include <iostream> 3 #include <string> 4 #include <queue> 5 #include <vector> 6 #include <map> 7 using namespace std; 8 9 #define MEM(a,v) memset (a,v,sizeof(a)) 10 // a for address, v for value 11 12 #define max(x,y) ((x)>(y)?(x):(y)) 13 #define max(x,y) ((x)>(y)?(x):(y)) 14 15 #define debug printf("!\n") 16 17 const int L = 10010; 18 const int INF = 1<<27; 19 20 int n; 21 22 struct node 23 { 24 int x,w; 25 26 node(){} 27 node(int a,int b) 28 { x= a;w =b;} 29 30 bool operator <(const node& a) const 31 { 32 return w<a.w; 33 } 34 }; 35 36 vector<node> va[L]; 37 int dis[L]; 38 39 40 void Dijkstra(int s) 41 { 42 int i; 43 for(i=0;i<=n;i++) 44 dis[i] = INF; 45 46 dis[s] = 0; 47 48 priority_queue<node> q; 49 q.push(node(s,dis[s])); 50 51 while(!q.empty()) 52 { 53 node t = q.top(); 54 q.pop(); 55 56 int x = t.x; 57 58 for(i = 0;i<va[x].size();i++) 59 { 60 node y = va[x][i]; 61 if(dis[y.x]>y.w+t.w) 62 { 63 dis[y.x] = y.w+t.w; 64 q.push(node(y.x,dis[y.x])); 65 } 66 } 67 } 68 } 69 70 71 72 int main() 73 { 74 int i,j; 75 76 bool flag; 77 78 char begin[32],end[32]; 79 char c[32],d[32]; 80 81 map<string,int> mp; 82 83 int w,k; 84 85 while(scanf("%d",&n)!=EOF && n!=-1) 86 { 87 88 mp.clear(); 89 90 for(i = 0;i<=n;i++) 91 va[i].clear(); 92 93 flag = false; 94 95 scanf("%s%s",begin,end); 96 97 if(strcmp(begin,end) == 0) 98 flag = true; 99 100 mp[begin] = 1; 101 mp[end] = 2; 102 103 k = 3; 104 105 for(i = 0;i<n;i++) 106 { 107 scanf("%s%s%d",c,d,&w); 108 109 if(!mp[c]) 110 mp[c] = k++; 111 if(!mp[d]) 112 mp[d] = k++; 113 114 va[mp[c]].push_back(node(mp[d],w)); 115 } 116 117 118 if(flag) 119 { 120 printf("0\n"); 121 continue; 122 } 123 Dijkstra(1); 124 if(dis[2]!=INF) 125 printf("%d\n",dis[2]); 126 else 127 printf("-1\n"); 128 } 129 130 return 0; 131 }
UPDATE:
AC,780MS
#include <iostream> #include <string> #include <cstring> #include <cstdlib> #include <cstdio> #include <cmath> #include <algorithm> #include <stack> #include <queue> #include <cctype> #include <vector> #include <iterator> #include <set> #include <map> #include <sstream> using namespace std; #define mem(a,b) memset(a,b,sizeof(a)) #define pf printf #define sf scanf #define spf sprintf #define pb push_back #define debug printf("!\n") #define INF 10000 #define MAXN 5010 #define MAX(a,b) a>b?a:b #define blank pf("\n") #define LL long long #define ALL(x) x.begin(),x.end() #define INS(x) inserter(x,x.begin()) #define pqueue priority_queue #define INF 0x3f3f3f3f int n,k; int g[155][155];//map int vis[155],d[155]; char name[155][35],str1[35],str2[35]; int dijkstra(int v) { int i,j,min,dir; for(i=0;i<k;i++) { vis[i]=0; d[i]=g[v][i]; } vis[v] = 1; d[v]=0; for(i = 0;i<k;i++) { min = INF; for(j=0;j<k;j++) { if(!vis[j] && min>d[j]) { min = d[j]; dir = j; } } if(min==INF) break; vis[dir]=1; for(j=0;j<k;j++) { if(!vis[j] && d[j] > d[dir]+g[dir][j]) d[j] = d[dir]+g[dir][j]; } } return d[1]; } int main() { int a,num1,num2,i,j; while(sf("%d",&n)==1 && n!=-1) { mem(g,63); sf("%s %s",name[0],name[1]); k=2; for(i = 0;i<n;i++) { sf("%s %s %d",str1,str2,&a); for(j = 0;j<k;j++) { if(strcmp(str1,name[j])==0) { num1 = j; break; } } if(j==k) { num1 = k; strcpy(name[k++],str1); } for(j = 0;j<k;j++) { if(strcmp(str2,name[j])==0) { num2 = j; break; } } if(j==k) { num2 = k; strcpy(name[k++],str2); } if(g[num1][num2]>a) g[num1][num2]=a; if(g[num2][num1]>a) g[num2][num1]=a; } if(strcmp(name[0],name[1])==0) pf("0\n"); else { i = dijkstra(0); if(i>=INF) pf("-1\n"); else pf("%d\n",i); } } }
