hdu1150
最小顶点覆盖
hdu1498 50 years, 50 colors
最小顶点覆盖 +枚举
1 #include <iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<stdlib.h> 6 #include<vector> 7 #include<cmath> 8 #include<queue> 9 #include<set> 10 using namespace std; 11 #define N 105 12 #define LL long long 13 #define INF 0xfffffff 14 const double eps = 1e-8; 15 const double pi = acos(-1.0); 16 const double inf = ~0u>>2; 17 vector<int>ed[N]; 18 struct node 19 { 20 int x,y; 21 }; 22 vector<node>pa[N]; 23 bool vis[2*N],f[N]; 24 int mat[N<<1],o[N],co[N]; 25 int dfs(int u) 26 { 27 int i; 28 for(i = 0 ;i < ed[u].size() ; i++) 29 { 30 int v = ed[u][i]; 31 if(vis[v]) continue; 32 vis[v] = 1; 33 if(mat[v]==-1||dfs(mat[v])) 34 { 35 mat[v] = u; 36 return 1; 37 } 38 } 39 return 0; 40 } 41 int main() 42 { 43 int n,k,i,j; 44 while(scanf("%d%d",&n,&k)&&n&&k) 45 { 46 memset(f,0,sizeof(f)); 47 for(i = 1; i <=100 ;i++) 48 pa[i].clear(); 49 int m = 0 ; 50 for(i = 1; i <= n ;i++) 51 for(j = 1 ;j <= n ;j++) 52 { 53 int x; 54 node a; 55 a.x = i;a.y = j; 56 scanf("%d",&x); 57 if(!f[x]) 58 { 59 f[x] = 1; 60 m++; 61 co[m] = x; 62 } 63 pa[x].push_back(a); 64 } 65 int g = 0; 66 for(i = 1; i <= m; i++) 67 { 68 memset(mat,-1,sizeof(mat)); 69 int c = co[i]; 70 for(j = 1; j <= n; j++) 71 ed[j].clear(); 72 for(j = 0 ;j < pa[c].size() ; j++) 73 { 74 node a = pa[c][j]; 75 ed[a.x].push_back(a.y+n); 76 } 77 int cnt = 0; 78 for(j = 1; j <= n ;j++) 79 { 80 memset(vis,0,sizeof(vis)); 81 if(dfs(j)) 82 cnt++; 83 } 84 if(cnt>k) 85 o[++g] = c; 86 } 87 if(g==0) 88 { 89 puts("-1"); 90 continue; 91 } 92 sort(o+1,o+g+1); 93 for(i =1 ;i < g ; i++) 94 cout<<o[i]<<" "; 95 cout<<o[i]<<endl; 96 } 97 return 0; 98 }
hdu2119
最小顶点覆盖 裸
1 #include <iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<stdlib.h> 6 #include<vector> 7 #include<cmath> 8 #include<queue> 9 #include<set> 10 using namespace std; 11 #define N 110 12 #define LL long long 13 #define INF 0xfffffff 14 const double eps = 1e-8; 15 const double pi = acos(-1.0); 16 const double inf = ~0u>>2; 17 vector<int>ed[N]; 18 bool vis[N<<1]; 19 int mat[N<<1]; 20 int dfs(int u) 21 { 22 int i; 23 for(i = 0 ;i < ed[u].size(); i++) 24 { 25 int v = ed[u][i]; 26 if(vis[v]) continue; 27 vis[v] = 1; 28 if(mat[v]==-1||dfs(mat[v])) 29 { 30 mat[v] = u; 31 return 1; 32 } 33 } 34 return 0; 35 } 36 37 int main() 38 { 39 int n,i,j,m; 40 while(cin>>n) 41 { 42 if(!n) break; 43 cin>>m; 44 memset(mat,-1,sizeof(mat)); 45 for(i = 1 ;i <= n;i++) 46 ed[i].clear(); 47 for(i = 1 ;i <= n ;i++) 48 for(j = 1 ;j <= m ;j++) 49 { 50 int x; 51 cin>>x; 52 if(x) 53 ed[i].push_back(j+n); 54 } 55 int ans = 0; 56 for(i = 1 ;i <= n;i++) 57 { 58 memset(vis,0,sizeof(vis)); 59 if(dfs(i)) 60 ans++; 61 } 62 cout<<ans<<endl; 63 } 64 return 0; 65 }
hdu1054 Strategic Game
最小顶点覆盖 不确定左右子集 建双向边 答案/2
1 #include <iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<stdlib.h> 6 #include<vector> 7 #include<cmath> 8 #include<queue> 9 #include<set> 10 using namespace std; 11 #define N 1510 12 #define LL long long 13 #define INF 0xfffffff 14 const double eps = 1e-8; 15 const double pi = acos(-1.0); 16 const double inf = ~0u>>2; 17 int mat[N]; 18 bool vis[N]; 19 vector<int>ed[N]; 20 int dfs(int u) 21 { 22 int i; 23 for(i = 0; i < ed[u].size(); i++) 24 { 25 int v = ed[u][i]; 26 if(vis[v]) continue; 27 vis[v] = 1; 28 if(mat[v]==-1||dfs(mat[v])) 29 { 30 mat[v] = u; 31 return 1; 32 } 33 } 34 return 0; 35 } 36 int main() 37 { 38 int n,i; 39 while(scanf("%d",&n)!=EOF) 40 { 41 memset(mat,-1,sizeof(mat)); 42 memset(vis,0,sizeof(vis)); 43 for(i = 0 ; i < n; i++) 44 ed[i].clear(); 45 for(i = 0 ; i < n ;i++) 46 { 47 int u,v,k; 48 scanf("%d%*c%*c%d%*c",&u,&k); 49 while(k--) 50 { 51 scanf("%d",&v); 52 ed[u].push_back(v); 53 ed[v].push_back(u); 54 } 55 } 56 int ans =0; 57 for(i = 0 ;i < n ;i++) 58 { 59 memset(vis,0,sizeof(vis)); 60 if(dfs(i)) 61 ans++; 62 } 63 printf("%d ",ans/2); 64 } 65 return 0; 66 }
hdu1151 Air Raid
最小路径覆盖 裸
1 #include <iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<stdlib.h> 6 #include<vector> 7 #include<queue> 8 #include<cmath> 9 using namespace std; 10 #define N 1010 11 vector<int>pa[N]; 12 bool fx[N],fy[N]; 13 int vis[N],mat[N]; 14 int find(int u) 15 { 16 int i; 17 for(i = 0 ; i < (int)pa[u].size() ; i++) 18 { 19 int v = pa[u][i]; 20 if(vis[v]) continue; 21 vis[v] = 1; 22 if(mat[v]==0||find(mat[v])) 23 { 24 mat[v] = u; 25 return 1; 26 } 27 } 28 return 0; 29 } 30 int main() 31 { 32 int n,m,i,t; 33 scanf("%d",&t); 34 while(t--) 35 { 36 scanf("%d%d",&n,&m); 37 memset(mat,0,sizeof(mat)); 38 for(i = 1; i <= 1000 ; i++) 39 pa[i].clear(); 40 for(i = 1; i <= m ;i++) 41 { 42 int v,u; 43 scanf("%d%d",&u,&v); 44 pa[u].push_back(v+n); 45 } 46 int s = 0; 47 for(i = 1; i <= n ;i++) 48 { 49 memset(vis,0,sizeof(vis)); 50 if(find(i)) 51 s++; 52 } 53 printf("%d ",n-s); 54 } 55 return 0; 56 }
hdu1350 Taxi Cab Scheme
最小路径覆盖
根据时间限制建边 注意：当前结束点与下一个开始点不同也可以建边
1 #include <iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<stdlib.h> 6 #include<vector> 7 #include<cmath> 8 #include<queue> 9 #include<set> 10 using namespace std; 11 #define N 510 12 #define LL long long 13 #define INF 0xfffffff 14 const double eps = 1e-8; 15 const double pi = acos(-1.0); 16 const double inf = ~0u>>2; 17 vector<int>ed[N]; 18 int ma[N][N],mat[N]; 19 bool vis[N]; 20 struct node 21 { 22 int t,u,v; 23 int u1,u2,v1,v2; 24 int d; 25 }p[N]; 26 int dfs(int u) 27 { 28 int i; 29 for(i = 0; i < ed[u].size() ; i++) 30 { 31 int v = ed[u][i]; 32 if(vis[v]) continue; 33 vis[v] = 1; 34 if(mat[v]==-1||dfs(mat[v])) 35 { 36 mat[v] = u; 37 return 1; 38 } 39 } 40 return 0; 41 } 42 int main() 43 { 44 int n,m,i,j; 45 int mod = 24*60; 46 cin>>n; 47 while(n--) 48 { 49 cin>>m; 50 memset(ma,0,sizeof(ma)); 51 memset(mat,-1,sizeof(mat)); 52 for(i = 1; i <= m ;i++) 53 ed[i].clear(); 54 int g = 0; 55 for(i = 1; i<= m ;i++) 56 { 57 int x,y,u1,u2,v1,v2; 58 scanf("%d%*c%d%d%d%d%d",&x,&y,&p[i].u1,&p[i].v1,&p[i].u2,&p[i].v2); 59 /*if(!ma[u1][v1]) 60 { 61 g++; 62 ma[u1][v1] = g; 63 } 64 if(!ma[u2][v2]) 65 { 66 g++; 67 ma[u2][v2] = g; 68 } 69 p[i].u = ma[u1][v1],p[i].v = ma[u2][v2];*/ 70 p[i].d = abs(p[i].u1-p[i].u2)+abs(p[i].v1-p[i].v2); 71 p[i].t = x*60+y; 72 } 73 for(i = 1 ;i <= m ;i++) 74 { 75 for(j = i+1 ;j <= m; j++) 76 { 77 int tt = abs(p[i].u2-p[j].u1)+abs(p[i].v2-p[j].v1); 78 if(p[i].t+p[i].d+tt<p[j].t) 79 { 80 ed[i].push_back(j); 81 } 82 } 83 } 84 int ans = 0; 85 for(i = 1;i <= m ;i++) 86 { 87 memset(vis,0,sizeof(vis)); 88 if(dfs(i)) 89 ans++; 90 } 91 cout<<m-ans<<endl; 92 } 93 return 0; 94 }