1 #include <iostream>
 2 #include<bits/stdc++.h>
 3 #include <stack>
 4 #include <queue>
 5 #include <map>
 6 #include <set>
 7 #include <cstdio>
 8 #include <cstring>
 9 #include <algorithm>
10 #include <math.h>
11 using namespace std;
12 typedef long long ll;
13 typedef unsigned long long ull;
14 const int MAX=1e5+5;
15 int n;
16 int an=0,ans;
17 bool vi[MAX];
18 int main()
19 {
20     scanf("%d",&n);
21     int tem;
22     ans=0;
23     for(int i=0;i<2*n;i++)
24     {
25         scanf("%d",&tem);
26         if(vi[tem])
27             an--;
28         else
29         {
30             an++;
31             ans=max(an,ans);
32             vi[tem]=true;
33         }
34 
35     }
36     printf("%d\n",ans);
37 }

 1 #include <iostream>
 2 #include<bits/stdc++.h>
 3 #include <stack>
 4 #include <queue>
 5 #include <map>
 6 #include <set>
 7 #include <cstdio>
 8 #include <cstring>
 9 #include <algorithm>
10 #include <math.h>
11 using namespace std;
12 typedef long long ll;
13 typedef unsigned long long ull;
14 const int MAX=6e4+5;
15 int n;
16 int lo[MAX],v[MAX];
17 bool test(double t)
18 {
19     double zuo=0.0,you=(double)1e18;
20     double teml,temr;
21     for(int i=0;i<n;i++)
22     {
23         teml=(double)lo[i]-t*(double)v[i];
24         temr=(double)lo[i]+t*(double)v[i];
25         zuo=max(teml,zuo);you=min(you,temr);
26         if(zuo-you>0.0000001)
27             return false;
28     }
29     return true;
30 }
31 int main()
32 {
33     scanf("%d",&n);
34     for(int i=0;i<n;i++)
35         scanf("%d",&lo[i]);
36     for(int i=0;i<n;i++)
37         scanf("%d",&v[i]);
38     double l=0.0,r=1000000000.0,mid;
39     while(r-l>0.0000001)
40     {
41         mid=(l+r)/(double)2.0;
42         if(test(mid))
43             r=mid;
44         else
45             l=mid;
46     }
47     printf("%.7f\n",mid);
48 
49 
50 }

 1 #include <iostream>
 2 #include<bits/stdc++.h>
 3 #include <stack>
 4 #include <queue>
 5 #include <map>
 6 #include <set>
 7 #include <cstdio>
 8 #include <cstring>
 9 #include <algorithm>
10 #include <math.h>
11 using namespace std;
12 typedef long long ll;
13 typedef unsigned long long ull;
14 const int MAX=2e5+5;
15 int col[MAX];
16 vector <int> v[MAX];
17 int n;
18 int x,y;
19 bool vi[MAX];
20 int an=0;
21 int pos;
22 void dfs(int k,int t)
23 {
24     int lo;
25     int num=1;
26     for(int i=0;i<v[k].size();i++)
27     {
28         lo=v[k][i];
29         if(!vi[lo])
30         {
31             for(int s=num;s<=an;s++)
32             {
33                 if(s!=col[k]&&s!=col[t])
34                 {
35                     col[lo]=s;
36                     num=s+1;
37                     break;
38                 }
39             }
40             vi[lo]=true;
41             dfs(lo,k);
42         }
43     }
44     v[k].clear();
45 }
46 int main()
47 {
48     scanf("%d",&n);
49     for(int i=0;i<n-1;i++)
50     {
51         scanf("%d %d",&x,&y);
52         v[x].push_back(y);
53         v[y].push_back(x);
54     }
55     for(int i=1;i<=n;i++)
56     {
57         if(v[i].size()>=an)
58         {
59             pos=i;
60             an=v[i].size()+1;
61         }
62     }
63     printf("%d\n",an);
64     col[pos]=1;
65     vi[pos]=true;
66     dfs(pos,-1);
67     for(int i=1;i<=n;i++)
68         printf("%d ",col[i]);
69     printf("\n");
70 }

 1 #include <iostream>
 2 #include<bits/stdc++.h>
 3 #include <stack>
 4 #include <queue>
 5 #include <map>
 6 #include <set>
 7 #include <cstdio>
 8 #include <cstring>
 9 #include <algorithm>
10 #include <math.h>
11 using namespace std;
12 typedef long long ll;
13 typedef unsigned long long ull;
14 const int MAX=1e3+5;
15 string a[MAX],b[MAX];
16 set <string> re,ret;
17 string x,y;
18 int n;
19 int main()
20 {
21     cin>>n;
22     for(int i=0;i<n;i++)
23     {
24         cin>>x>>y;
25         a[i]=x.substr(0,3);
26         b[i]=x.substr(0,2)+y.substr(0,1);
27         if(re.count(a[i]))
28             ret.insert(a[i]);
29         re.insert(a[i]);
30     }
31     re.clear();
32     for(int i=0;i<n;i++)
33     {
34         if(!re.count(b[i]))
35         {
36             a[i]=b[i];
37             re.insert(b[i]);
38         }
39         else
40         {
41             if(ret.count(a[i])||re.count(a[i]))
42             {
43                 printf("NO\n");
44                 return 0;
45             }
46             re.insert(a[i]);
47         }
48     }
49     printf("YES\n");
50     for(int i=0;i<n;i++)
51         cout<<a[i]<<"\n";
52 }