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 }
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 }
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 }
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 }
