2018 Spring Single Training B （uva 572，HihoCoder 1632，POJ 2387，POJ 2236，UVA 10054，HDU 2141）

这场比赛可以说是灰常的水了，涨信心场？？

今下午义务劳动，去拿着锄头发了将近一小时呆，发现自己实在是干不了什么，就跑到实验室打比赛了~

之前的比赛补题补了这么久连一场完整的都没补完，结果这场比完后一小时连题解都出来了···

A-烤肉拌饭 （ uva 572）

就是求联通块的数量啊，刚学dfs的时候做的那种！

 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <iostream>
 #include <queue>

 using namespace std;
 const int maxn=+;
 const int dx[]={,-,,-,,-,,};
 const int dy[]={,,,,-,-,,-};
 char G[maxn][maxn];
 int vis[maxn][maxn];
 int n,m;
 int ans;
 void dfs(int x,int y){
     vis[x][y]=;
     for(int i=;i<;i++){
         int nx=x+dx[i];
         int ny=y+dy[i];
         if(nx>=&&nx<=n&&ny>=&&ny<=m&&G[nx][ny]=='@'&&!vis[nx][ny]){
             dfs(nx,ny);
         }
     }
     return ;
 }
 int main(){
     while(scanf("%d%d",&n,&m)&&n&&m){
         memset(vis,,sizeof(vis));
         ans=;
         for(int i=;i<=n;i++){
             for(int j=;j<=m;j++){
                 scanf(" %c",&G[i][j]);
             }
         }
         for(int i=;i<=n;i++){
             for(int j=;j<=m;j++){
                 if(!vis[i][j]&&G[i][j]=='@'){
                     ans++;
                     dfs(i,j);
                 }
             }
         }
         cout<<ans<<endl;
     }
 return ;
 }

 

 

B-麻辣香锅 HihoCoder - 1632

模拟，emmm模拟可以提高代码能力？？

C-啵啵鱼 poj2387

是个很裸的最短路，一个spfa或者dijsktra就可以

 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <iostream>
 #include <queue>

 using namespace std;
 const int maxn=+;
 const int maxm=+;
 const int INF=;
 typedef long long LL;
 int head[maxn],Next[maxm],to[maxm];
 LL val[maxm];
 int sz;
 int n,m;
 void add_edge(int a,int b,LL w){
     ++sz;
     val[sz]=w;
     to[sz]=b;
     Next[sz]=head[a];
     head[a]=sz;
 }
 LL d[maxn];
 int spfa(int s){
     for(int i=;i<=n;i++)d[i]=INF;
     int vis[maxn];
     memset(vis,,sizeof(vis));
     queue<int>q;
     q.push(s);
     vis[s]=;
     d[s]=;
     while(!q.empty()){
         int u=q.front();q.pop();vis[u]=;
         for(int i=head[u];i;i=Next[i]){
             int v=to[i];
             if(d[v]>d[u]+val[i]){
                 d[v]=d[u]+val[i];
                 if(!vis[v]){
                     vis[v]=;
                     q.push(v);
                 }
             }
         }
     }
     return d[];
 }
 int main(){
     sz=;
     memset(head,,sizeof(head));
     scanf("%d%d",&m,&n);
     int a,b;LL c;
     for(int i=;i<=m;i++){
         scanf("%d %d%lld",&a,&b,&c);
       //  cout<<a<<" "<<b<<" "<<c<<endl;
         add_edge(a,b,c);
         add_edge(b,a,c);
     }
     cout<<spfa(n);
 return ;
 }

D-海底捞 POJ2236

卢老师一句话点醒梦中人，直接并查集就可以~

 #include <cstdio>
 #include <algorithm>
 #include <iostream>
 #include <cstring>
 using namespace std;
 const int maxn=+;
 int n,d;
 int a,b;
 char c;
 int p[maxn],vis[maxn];
 struct Node{
     int x,y;
 }node[maxn];
 int find(int x){
     return p[x]==x?x:p[x]=find(p[x]);
 }
 bool dist(Node A,Node B){
     if((A.x-B.x)*(A.x-B.x)+(A.y-B.y)*(A.y-B.y)<=d*d)
         return true;
     return false;
 }
 int main(){
     scanf("%d%d",&n,&d);
     for(int i=;i<=n;i++){
         scanf("%d%d",&node[i].x,&node[i].y);
     }
     for(int i=;i<=n;i++)p[i]=i;
     while(scanf(" %c",&c)!=EOF){
         if(c=='O'){
             scanf("%d",&a);
             vis[a]=;
             for(int i=;i<=n;i++){
                 if(vis[i]&&i!=a&&dist(node[a],node[i])){
                    // cout<<a<<"-->"<<i<<endl;
                     int x=find(a),y=find(i);
                     if(x!=y)p[x]=y;
                 }
             }
         }
         if(c=='S'){
             scanf("%d%d",&a,&b);
             int x=find(a),y=find(b);
             //cout<<":"<<x<<y<<endl;
             if(x==y){
                 printf("SUCCESS\n");
             }else{
                 printf("FAIL\n");
             }
         }
     }
     return ;
 }

E-黄焖鸡 uva10054

这个题以前做过，欧拉回路，注意打印的时候逆序输出

 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <iostream>
 #include <queue>

 using namespace std;
 const int maxn=+;

 int T;
 int G[maxn][maxn];
 int n;
 int deg[maxn];
 int a,b;
 int M;
 int p[maxn];
 int find(int x){
     return p[x]==x?x:find(p[x]);
 }
 void dfs(int u){
     for(int i=;i<=M;i++){
         if(G[u][i]){
             G[u][i]--;
             G[i][u]--;
             dfs(i);
             cout<<i<<" "<<u<<endl;
         }
     }
     return;
 }
 int main(){
     scanf("%d",&T);
     for(int t=;t<=T;t++){
         if(t!=)cout<<""<<endl;
         memset(G,,sizeof(G));
         memset(deg,,sizeof(deg));
         printf("Case #%d\n",t);
         M=-;
         scanf("%d",&n);
         for(int i=;i<=;i++)p[i]=i;
         for(int i=;i<=n;i++){
             scanf("%d%d",&a,&b);
             M=max(M,max(a,b));
             G[a][b]++;
             G[b][a]++;
             deg[a]++;
             deg[b]++;
             int x=find(a),y=find(b);
             if(x!=y)p[x]=y;

         }
         bool judge=;
         for(int i=;i<=M;i++){
             if(deg[i]){
                 if(find(i)!=find(M)||deg[i]%){
                     judge=;
                     break;
                 }
             }
         }
         if(!judge){
             cout<<"some beads may be lost"<<endl;
         }else{
         for(int i=;i<=M;i++)
             dfs(i);
         }

     }
 return ;
 }

F- 减肥成功指日可待 hdu2141

用set或者二分。但是set再G++下会MLE必须要选择C++才能AC，雾···

 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <iostream>
 #include <set>
 #include <vector>
 using namespace std;
 const int maxn=+;
 typedef long long LL;
 int A,B,C,s,x;
 LL a[maxn],b[maxn],c[maxn];
 int kase;
 int main(){
     while(scanf("%d%d%d",&A,&B,&C)!=EOF){
     kase++;
     set<LL>S;
     printf("Case %d:\n",kase);
     for(int i=;i<=A;i++){
         scanf("%lld",&a[i]);
     }
     for(int i=;i<=B;i++){
         scanf("%lld",&b[i]);
     }
     for(int i=;i<=C;i++){
         scanf("%lld",&c[i]);
     }
     for(int i=;i<=A;i++){
         for(int j=;j<=B;j++){
             //for(int l=1;l<=C;l++){
                 LL X=a[i]+b[j];
                 if(!S.count(X))
                     S.insert(X);
            // }
         }
     }
     scanf("%d",&s);
     LL x;
     for(int i=;i<=s;i++){
         scanf("%lld",&x);
         bool ok=;
         for(int i=;i<=C;i++){
             LL pos=x-c[i];
             //if(pos<0)continue;
             if(S.count(pos)){
                 ok=;
                 break;
             }
         }
         //if(S.count(x))cout<<"YES"<<endl;
         if(ok)cout<<"YES"<<endl;
         else
             cout<<"NO"<<endl;
     }
     }
 return ;
 }