Codeforces Round #267 (Div. 2)

A

 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 100000

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 main()

18 {

19     int n,i,j;

20     int ans = 0;

21     cin>>n;

22     for(i = 1; i <= n; i++)

23     {

24         int x,y;

25         scanf("%d%d",&x,&y);

26         if(y-x>=2) ans++;

27     }

28     cout<<ans<<endl;

29     return 0;

30 }

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B

还以为是间接的朋友，写复杂了，没想到那么简单。

 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 1010

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 a[N];

18 int fa[N];

19 int r[N];

20 int find(int x)

21 {

22     if(x!=fa[x])

23     {

24         fa[x] = find(fa[x]);

25         return fa[x];

26     }

27     return x;

28 }

29 int main()

30 {

31     int n,m,k,i,j;

32     cin>>n>>m>>k;

33     for(i = 1 ;i <= m+1; i++) {fa[i] = i;r[i] = 1;}

34     for(i = 1; i <= m+1; i++)

35     scanf("%d",&a[i]);

36     int ans = 0;

37     for(i = 1 ; i <= m; i++)

38     {

39         int cnt = 0;

40         for(int g = 0 ; g < n ;g++)

41             if((a[m+1]&(1<<g))!=(a[i]&(1<<g))) cnt++;

42             if(cnt<=k) ans++;

43     }

44 //    for(i = 1; i <= m+1; i++)

45 //        for(j = 1; j <= m+1; j++)

46 //        {

47 //            if(i==j) continue;

48 //            int cnt = 0;

49 //            for(int g = 0 ; g < n ;g++)

50 //            if((i&(1<<g))!=(i&(1<<g))) cnt++;

51 //            if(cnt<=k)

52 //            {

53 //                int tx = find(i);

54 //                int ty = find(j);

55 //                if(tx!=ty)

56 //                {

57 //                    fa[tx] = ty;

58 //                    r[tx]+=r[ty];

59 //                }

60 //            }

61 //        }

62 //    int kk = find(m+1);

63     cout<<ans<<endl;

64     return 0;

65 }

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　C

简单dp

 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 5010

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 a[N];

18 LL dp[N][N];

19 LL sum[N];

20 int main()

21 {

22     int n,m,k,i,j;

23     cin>>n>>m>>k;

24     for(i = 1; i <= n;  i++)

25     {

26         scanf("%d",&a[i]);

27         sum[i] = sum[i-1]+a[i];

28     }

29     for(i = m; i <= n ;i++)

30     {

31         for(j = 1; j <= k; j++)

32         dp[i][j] = max(dp[i-m][j-1]+sum[i]-sum[i-m],dp[i-1][j]);

33     }

34     cout<<dp[n][k]<<endl;

35     return 0;

36 }

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D

tarjan缩点+dfs

dfs的时候少写了else里面的内容。。一直wa到结束

  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 #include<map>

 11 #include<stack>

 12 using namespace std;

 13 #define N 500010

 14 #define M 500010

 15 #define LL long long

 16 #define INF 0xfffffff

 17 const double eps = 1e-8;

 18 const double pi = acos(-1.0);

 19 const double inf = ~0u>>2;

 20 struct node

 21 {

 22     int u,v,next,w;

 23 } edge[M];

 24 int t,low[N],pre[N],sccno[N],head[N],scc,dep,vis[N],dis[N];

 25 int dd1[N],dd2[N];

 26 int dp[N];

 27 int num[N],de[N];

 28 vector<int>cd[N];

 29 void init()

 30 {

 31     t = 0;

 32     memset(head,-1,sizeof(head));

 33 }

 34 void add(int u,int v)

 35 {

 36     edge[t].u  =u;

 37     edge[t].v = v;

 38     edge[t].next = head[u];

 39     head[u] = t++;

 40 }

 41 stack<int>s;

 42 void dfs(int u)

 43 {

 44     low[u] = pre[u] = ++dep;

 45     s.push(u);

 46     for(int i = head[u] ; i!=-1 ; i = edge[i].next)

 47     {

 48         int v = edge[i].v;

 49         if(!pre[v])

 50         {

 51             dfs(v);

 52             low[u] = min(low[u],low[v]);

 53         }

 54         else if(!sccno[v])

 55             low[u] = min(low[u],pre[v]);

 56     }

 57     if(low[u]==pre[u])

 58     {

 59         scc++;

 60         int minz = INF,sum=INF;

 61         for(;;)

 62         {

 63             int x = s.top();

 64             s.pop();

 65             if(minz>num[x])

 66             {

 67                 minz = num[x];

 68                 sum = dp[x];

 69             }

 70             else if(minz==num[x]) sum = min(dp[x],sum);

 71             sccno[x] = scc;

 72             if(x==u)break;

 73         }

 74         dd1[scc] = minz;

 75         dd2[scc] = sum;

 76 

 77     }

 78 }

 79 void find_scc(int n)

 80 {

 81     scc=0;

 82     dep=0;

 83     memset(low,0,sizeof(low));

 84     memset(pre,0,sizeof(pre));

 85     memset(sccno,0,sizeof(sccno));

 86     for(int i = 1; i <= n ; i++)

 87         if(!pre[i])

 88             dfs(i);

 89 }

 90 map<string,int>f;

 91 vector<int>ed[N];

 92 char s1[N],s2[N];

 93 int a[N];

 94 int judge(char *str)

 95 {

 96     int i,k;

 97     k= strlen(str);

 98     int cnt = 0;

 99     for(i = 0 ; i < k; i++)

100         if(str[i]=='R')

101             cnt++;

102     return cnt;

103 }

104 int ddfs(int u)

105 {

106     int i,j;

107     for(i = 0 ; i< ed[u].size() ; i++)

108     {

109         int v = ed[u][i];

110         if(!vis[v])

111         {

112             vis[v] = 1;

113             int ss = ddfs(v);

114             if(dd1[u]>=ss)

115             {

116                 if(dd1[u]==ss)

117                     dd2[u] = min(dd2[u],dd2[v]);

118                 else dd2[u] = dd2[v];

119                 dd1[u] = ss;

120             }

121         }

122         else if(dd1[u]>=dd1[v])

123         {

124             if(dd1[u]==dd1[v]) dd2[u] = min(dd2[u],dd2[v]);

125             else dd2[u] = dd2[v];

126             dd1[u] = dd1[v];

127         }

128     }

129     return dd1[u];

130 }

131 int main()

132 {

133     init();

134     int m,i,j,n;

135     scanf("%d",&m);

136     int g = 0;

137     for(i = 1; i <= m ; i++)

138     {

139         scanf("%s",s1);

140         int len = strlen(s1);

141         for(j = 0 ; j <  len; j++) if(s1[j]>='a'&&s1[j]<='z') s1[j]-=32;

142         if(!f[s1])

143         {

144             a[i] = ++g;

145             f[s1] = g;

146         }

147         else a[i] = f[s1];

148         num[a[i]] = judge(s1);

149         dp[a[i]] = len;

150     }

151     scanf("%d",&n);

152     for( i =1 ; i <= n ; i++)

153     {

154         int u,v;

155         scanf("%s%s",s1,s2);

156         int len1 =strlen(s1) ,len2 = strlen(s2);

157         for(j = 0 ; j <  len1; j++) if(s1[j]>='a'&&s1[j]<='z') s1[j]-=32;

158         for(j = 0 ; j <  len2; j++) if(s2[j]>='a'&&s2[j]<='z') s2[j]-=32;

159         if(!f[s1])

160         {

161             u = ++g;

162             f[s1] = g;

163         }

164         else u = f[s1];

165         if(!f[s2])

166         {

167             v = ++g;

168             f[s2] = g;

169         }

170         else v = f[s2];

171         add(u,v);

172         num[u] = judge(s1);

173         num[v] = judge(s2);

174         dp[u] = len1;

175         dp[v] = len2;

176         cd[u].push_back(v);

177     }

178     find_scc(g);

179     for(i = 1 ; i <= g; i++)

180     {

181         int u = sccno[i];

182         for(j = 0 ;j < cd[i].size() ; j++)

183         {

184             int v = sccno[cd[i][j]];

185             if(v==u) continue;

186             ed[u].push_back(v);

187             de[v] = 1;

188         }

189     }

190     memset(vis,0,sizeof(vis));

191     for(i = 1 ; i <= scc; i++)

192     {

193         if(!de[i])

194         {

195             vis[i] = 1;

196             ddfs(i);

197         }

198     }

199     LL ans = 0,sum=0;

200     for(i = 1 ; i<= m; i++)

201     {

202         int u = sccno[a[i]];

203         //cout<<u<<" "<<dd2[u]<<endl;

204         ans+=dd1[u];

205         sum+=dd2[u];

206     }

207     cout<<ans<<" "<<sum<<endl;

208     return 0;

209 }

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