1 #include<cstdio>
 2 #include<iostream>
 3 using namespace std;
 4 long long n,l,r,mid,ans;
 5 bool check(long long x){
 6     x>>=1;
 7     if(x&1){
 8         long long t1=x>>1,t2=(x>>1)+1;
 9         return t1*t2>=n;
10     }
11     return (x>>1)*(x>>1)>=n;
12 }
13 int main()
14 {
15     freopen("block.in","r",stdin);
16     freopen("block.out","w",stdout);
17     int T; scanf("%d",&T);
18     while(T--){
19         scanf("%lld",&n);
20         l=1; r=1e9;
21         while(l<=r){
22             mid=l+r>>1;
23             if(check(mid)) r=mid-1,ans=mid;
24             else l=mid+1;
25         }
26         printf("%lld\n",ans);
27     }return 0;
28 }

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<algorithm>
 4 #define MN 20005
 5 using namespace std;
 6 long long ans;
 7 int n,fa[MN],siz[MN];
 8 struct node{int u,v,w;}e[MN];
 9 bool cmp(node a,node b){return a.w<b.w;}
10 int ff(int u){return fa[u]==u?u:fa[u]=ff(fa[u]);}
11 void unite(int u,int v,int w){
12     u=ff(u); v=ff(v);
13     ans+=1LL*siz[u]*siz[v]*(w+1)-1;
14     fa[u]=v; siz[v]+=siz[u];
15 }
16 int main()
17 {
18     freopen("tree.in","r",stdin);
19     freopen("tree.out","w",stdout);
20     int T; scanf("%d",&T);
21     while(T--){
22         scanf("%d",&n); ans=0;
23         for(int i=1;i<=n;i++) fa[i]=i,siz[i]=1;
24         for(int i=1;i<n;i++)
25             scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);
26         sort(e+1,e+n,cmp);
27         for(int i=1;i<n;i++)
28             unite(e[i].u,e[i].v,e[i].w);
29         printf("%lld\n",ans);
30     }
31 }

 1 #include<cstdio>
 2 #include<iostream>
 3 #define MN 200005
 4 int a[MN],n;
 5 bool b[MN];
 6 int main()
 7 {
 8     freopen("ball.in","r",stdin);
 9     freopen("ball.out","w",stdout);
10     scanf("%d",&n);
11     for(int i=1;i<=n;i++) scanf("%d",&a[i]);
12     a[0]=0x7fffffff;
13     for(int i=1;i<=n/2;i++){
14         int t1=0,t2=0;
15         bool f=false;
16         for(int j=1;j<=n;j++)
17             if(!b[j]){
18                 f=f?0:1;
19                 if(f&&a[j]<a[t1]) t1=j;
20             }
21         b[t1]=true; f=false;
22         for(int j=t1+1;j<=n;j++)
23             if(!b[j]){
24                 f=f?0:1;
25                 if(f&&a[j]<a[t2]) t2=j;
26             }
27             else break;
28         b[t2]=true;
29         printf("%d %d ",a[t1],a[t2]);
30     }
31     return 0;
32 }