Codeforces Round #267 (Div. 2)

A

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<cmath>
 #include<queue>
 #include<set>
 using namespace std;
 #define N 100000
 #define LL long long
 #define INF 0xfffffff
 const double eps = 1e-;
 const double pi = acos(-1.0);
 const double inf = ~0u>>;
 int main()
 {
     int n,i,j;
     int ans = ;
     cin>>n;
     for(i = ; i <= n; i++)
     {
         int x,y;
         scanf("%d%d",&x,&y);
         if(y-x>=) ans++;
     }
     cout<<ans<<endl;
     return ;
 }

B

还以为是间接的朋友，写复杂了，没想到那么简单。

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<cmath>
 #include<queue>
 #include<set>
 using namespace std;
 #define N 1010
 #define LL long long
 #define INF 0xfffffff
 const double eps = 1e-;
 const double pi = acos(-1.0);
 const double inf = ~0u>>;
 int a[N];
 int fa[N];
 int r[N];
 int find(int x)
 {
     if(x!=fa[x])
     {
         fa[x] = find(fa[x]);
         return fa[x];
     }
     return x;
 }
 int main()
 {
     int n,m,k,i,j;
     cin>>n>>m>>k;
     for(i =  ;i <= m+; i++) {fa[i] = i;r[i] = ;}
     for(i = ; i <= m+; i++)
     scanf("%d",&a[i]);
     int ans = ;
     for(i =  ; i <= m; i++)
     {
         int cnt = ;
         for(int g =  ; g < n ;g++)
             if((a[m+]&(<<g))!=(a[i]&(<<g))) cnt++;
             if(cnt<=k) ans++;
     }
 //    for(i = 1; i <= m+1; i++)
 //        for(j = 1; j <= m+1; j++)
 //        {
 //            if(i==j) continue;
 //            int cnt = 0;
 //            for(int g = 0 ; g < n ;g++)
 //            if((i&(1<<g))!=(i&(1<<g))) cnt++;
 //            if(cnt<=k)
 //            {
 //                int tx = find(i);
 //                int ty = find(j);
 //                if(tx!=ty)
 //                {
 //                    fa[tx] = ty;
 //                    r[tx]+=r[ty];
 //                }
 //            }
 //        }
 //    int kk = find(m+1);
     cout<<ans<<endl;
     return ;
 }

　C

简单dp

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<cmath>
 #include<queue>
 #include<set>
 using namespace std;
 #define N 5010
 #define LL long long
 #define INF 0xfffffff
 const double eps = 1e-;
 const double pi = acos(-1.0);
 const double inf = ~0u>>;
 int a[N];
 LL dp[N][N];
 LL sum[N];
 int main()
 {
     int n,m,k,i,j;
     cin>>n>>m>>k;
     for(i = ; i <= n;  i++)
     {
         scanf("%d",&a[i]);
         sum[i] = sum[i-]+a[i];
     }
     for(i = m; i <= n ;i++)
     {
         for(j = ; j <= k; j++)
         dp[i][j] = max(dp[i-m][j-]+sum[i]-sum[i-m],dp[i-][j]);
     }
     cout<<dp[n][k]<<endl;
     return ;
 }

D

tarjan缩点+dfs

dfs的时候少写了else里面的内容。。一直wa到结束

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<cmath>
 #include<queue>
 #include<set>
 #include<map>
 #include<stack>
 using namespace std;
 #define N 500010
 #define M 500010
 #define LL long long
 #define INF 0xfffffff
 const double eps = 1e-;
 const double pi = acos(-1.0);
 const double inf = ~0u>>;
 struct node
 {
     int u,v,next,w;
 } edge[M];
 int t,low[N],pre[N],sccno[N],head[N],scc,dep,vis[N],dis[N];
 int dd1[N],dd2[N];
 int dp[N];
 int num[N],de[N];
 vector<int>cd[N];
 void init()
 {
     t = ;
     memset(head,-,sizeof(head));
 }
 void add(int u,int v)
 {
     edge[t].u  =u;
     edge[t].v = v;
     edge[t].next = head[u];
     head[u] = t++;
 }
 stack<int>s;
 void dfs(int u)
 {
     low[u] = pre[u] = ++dep;
     s.push(u);
     for(int i = head[u] ; i!=- ; i = edge[i].next)
     {
         int v = edge[i].v;
         if(!pre[v])
         {
             dfs(v);
             low[u] = min(low[u],low[v]);
         }
         else if(!sccno[v])
             low[u] = min(low[u],pre[v]);
     }
     if(low[u]==pre[u])
     {
         scc++;
         int minz = INF,sum=INF;
         for(;;)
         {
             int x = s.top();
             s.pop();
             if(minz>num[x])
             {
                 minz = num[x];
                 sum = dp[x];
             }
             else if(minz==num[x]) sum = min(dp[x],sum);
             sccno[x] = scc;
             if(x==u)break;
         }
         dd1[scc] = minz;
         dd2[scc] = sum;

     }
 }
 void find_scc(int n)
 {
     scc=;
     dep=;
     memset(low,,sizeof(low));
     memset(pre,,sizeof(pre));
     memset(sccno,,sizeof(sccno));
     for(int i = ; i <= n ; i++)
         if(!pre[i])
             dfs(i);
 }
 map<string,int>f;
 vector<int>ed[N];
 char s1[N],s2[N];
 int a[N];
 int judge(char *str)
 {
     int i,k;
     k= strlen(str);
     int cnt = ;
     for(i =  ; i < k; i++)
         if(str[i]=='R')
             cnt++;
     return cnt;
 }
 int ddfs(int u)
 {
     int i,j;
     for(i =  ; i< ed[u].size() ; i++)
     {
         int v = ed[u][i];
         if(!vis[v])
         {
             vis[v] = ;
             int ss = ddfs(v);
             if(dd1[u]>=ss)
             {
                 if(dd1[u]==ss)
                     dd2[u] = min(dd2[u],dd2[v]);
                 else dd2[u] = dd2[v];
                 dd1[u] = ss;
             }
         }
         else if(dd1[u]>=dd1[v])
         {
             if(dd1[u]==dd1[v]) dd2[u] = min(dd2[u],dd2[v]);
             else dd2[u] = dd2[v];
             dd1[u] = dd1[v];
         }
     }
     return dd1[u];
 }
 int main()
 {
     init();
     int m,i,j,n;
     scanf("%d",&m);
     int g = ;
     for(i = ; i <= m ; i++)
     {
         scanf("%s",s1);
         int len = strlen(s1);
         for(j =  ; j <  len; j++) if(s1[j]>='a'&&s1[j]<='z') s1[j]-=;
         if(!f[s1])
         {
             a[i] = ++g;
             f[s1] = g;
         }
         else a[i] = f[s1];
         num[a[i]] = judge(s1);
         dp[a[i]] = len;
     }
     scanf("%d",&n);
     for( i = ; i <= n ; i++)
     {
         int u,v;
         scanf("%s%s",s1,s2);
         int len1 =strlen(s1) ,len2 = strlen(s2);
         for(j =  ; j <  len1; j++) if(s1[j]>='a'&&s1[j]<='z') s1[j]-=;
         for(j =  ; j <  len2; j++) if(s2[j]>='a'&&s2[j]<='z') s2[j]-=;
         if(!f[s1])
         {
             u = ++g;
             f[s1] = g;
         }
         else u = f[s1];
         if(!f[s2])
         {
             v = ++g;
             f[s2] = g;
         }
         else v = f[s2];
         add(u,v);
         num[u] = judge(s1);
         num[v] = judge(s2);
         dp[u] = len1;
         dp[v] = len2;
         cd[u].push_back(v);
     }
     find_scc(g);
     for(i =  ; i <= g; i++)
     {
         int u = sccno[i];
         for(j =  ;j < cd[i].size() ; j++)
         {
             int v = sccno[cd[i][j]];
             if(v==u) continue;
             ed[u].push_back(v);
             de[v] = ;
         }
     }
     memset(vis,,sizeof(vis));
     for(i =  ; i <= scc; i++)
     {
         if(!de[i])
         {
             vis[i] = ;
             ddfs(i);
         }
     }
     LL ans = ,sum=;
     for(i =  ; i<= m; i++)
     {
         int u = sccno[a[i]];
         //cout<<u<<" "<<dd2[u]<<endl;
         ans+=dd1[u];
         sum+=dd2[u];
     }
     cout<<ans<<" "<<sum<<endl;
     return ;
 }