Codeforces Round #510 (Div. 2)
A.
模拟
//By SiriusRen #include <bits/stdc++.h> using namespace std; int n,m,a[105],sum,minn=10000,maxx,t; int main(){ scanf("%d%d",&n,&m); for(int i=1;i<=n;i++){ scanf("%d",&a[i]); sum+=a[i]; minn=min(minn,a[i]); maxx=max(maxx,a[i]); } for(int i=1;i<=n;i++)t+=maxx-a[i]; if(t>=m)minn=maxx; else sum+=m,minn=sum/n+((sum%n)!=0); maxx+=m; printf("%d %d\n",minn,maxx); }
B.
模拟
//By SiriusRen #include <bits/stdc++.h> using namespace std; map<string,int>mp; int n,a,r[10],ans; string b; int main(){ scanf("%d",&n); mp["A"]=1,mp["B"]=2,mp["C"]=3,mp["ABC"]=7; mp["AB"]=4,mp["BC"]=5,mp["AC"]=6; for(int i=1;i<=7;i++)r[i]=1000050; for(int i=1;i<=n;i++){ cin>>a>>b; sort(b.begin(),b.end()); r[mp[b]]=min(r[mp[b]],a); } ans=min(min(r[1]+r[2]+r[3],min(r[4]+r[3],min(r[5]+r[1],r[6]+r[2]))),r[7]); ans=min(ans,min(r[4]+r[5],min(r[5]+r[6],r[4]+r[6]))); if(ans>300000)ans=-1; printf("%d\n",ans); }
C.
分情况讨论
//By SiriusRen #include <bits/stdc++.h> using namespace std; const int N=200050; int n,rec,t,tp,vis[N]; struct Node{int id,wei;}node[N],del[N]; bool operator<(Node a,Node b){ if(a.wei!=b.wei)return a.wei<b.wei; return a.id<b.id; } int main(){ scanf("%d",&n); for(int i=1;i<=n;i++){ scanf("%d",&node[i].wei); node[i].id=i; } sort(node+1,node+1+n); for(int i=1;i<=n;i++){ if(node[i].wei>=0){rec=i-1;break;} if(i==n)rec=i; } if(rec&1)del[++tp]=node[rec]; for(int i=rec+1;i<=n;i++){ if(node[i].wei!=0)break; del[++tp]=node[i]; } if(tp!=n){ for(int i=1;i<tp;i++) printf("1 %d %d\n",del[i].id,del[i+1].id),vis[del[i].id]=1; if(tp)printf("2 %d\n",del[tp].id),vis[del[tp].id]=1; for(int i=1;i<=n;i++)if(!vis[node[i].id])node[++t]=node[i]; for(int i=1;i<t;i++)printf("1 %d %d\n",node[i].id,node[i+1].id); } else{ for(int i=1;i<n;i++)printf("1 %d %d\n",node[i].id,node[i+1].id); } }
D.
权值线段树
//By SiriusRen #include <bits/stdc++.h> using namespace std; typedef long long ll; const int N=400050; int n,tp,a[N],tree[N<<2]; ll t,s[N],sum[N],ans; void insert(int l,int r,int pos,int wei){ if(l==r){tree[pos]++;return;} int mid=(l+r)>>1,lson=pos<<1,rson=pos<<1|1; if(mid<wei)insert(mid+1,r,rson,wei); else insert(l,mid,lson,wei); tree[pos]=tree[lson]+tree[rson]; } int query(int l,int r,int pos,int L,int R){ if(l>=L&&r<=R)return tree[pos]; int mid=(l+r)>>1,lson=pos<<1,rson=pos<<1|1; if(mid<L)return query(mid+1,r,rson,L,R); else if(mid>=R)return query(l,mid,lson,L,R); else return query(l,mid,lson,L,R)+query(mid+1,r,rson,L,R); } int main(){ scanf("%d%lld",&n,&t);t--; for(int i=1;i<=n;i++)scanf("%d",&a[i]); for(int i=1;i<=n;i++) sum[i]=sum[i-1]+a[i],s[++tp]=t+sum[i-1],s[++tp]=sum[i]; sort(s+1,s+1+tp); for(int i=n;i;i--) insert(1,tp,1,lower_bound(s+1,s+1+tp,sum[i])-s), ans+=query(1,tp,1,1,lower_bound(s+1,s+1+tp,t+sum[i-1])-s); printf("%lld\n",ans); }
E.
DP（前缀和）
//By SiriusRen #include <bits/stdc++.h> using namespace std; const int N=1000005,mod=998244353; typedef long long ll; int n,m,xx,tp,f[N],cnt[N],s[N],sx,sy; int sumx[N],sumy[N],sumx2[N],sumy2[N]; struct Node{ int x,y,wei; Node(){} Node(int X,int Y,int Z){x=X,y=Y,wei=Z;} }node[N]; bool operator<(Node a,Node b){ return a.wei<b.wei; } int power(int x,int y){ int res=1; while(y){ if(y&1)res=1ll*res*x%mod; x=1ll*x*x%mod,y>>=1; }return res; } int main(){ scanf("%d%d",&n,&m); for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) scanf("%d",&xx),node[++tp]=Node(i,j,xx); sort(node+1,node+1+tp),node[0].wei=-1; scanf("%d%d",&sx,&sy); for(int i=1;i<=tp;i++){ if(node[i].wei==node[i-1].wei)cnt[i]=cnt[i-1]; else cnt[i]=i-1; sumx[i]=(sumx[i-1]+node[i].x)%mod; sumy[i]=(sumy[i-1]+node[i].y)%mod; sumx2[i]=(sumx2[i-1]+1ll*node[i].x*node[i].x)%mod; sumy2[i]=(sumy2[i-1]+1ll*node[i].y*node[i].y)%mod; } for(int i=1;i<=tp;i++){ f[i]=(-2ll*sumx[cnt[i]]%mod*node[i].x%mod-2ll*sumy[cnt[i]]%mod*node[i].y%mod)%mod; f[i]=((f[i]+sumx2[cnt[i]])%mod+sumy2[cnt[i]])%mod; f[i]=(f[i]+1ll*node[i].x*node[i].x%mod*cnt[i])%mod; f[i]=((f[i]+1ll*node[i].y*node[i].y%mod*cnt[i]%mod)%mod+mod)%mod; (f[i]+=s[cnt[i]])%=mod; f[i]=(1ll*f[i]*power(cnt[i],mod-2))%mod; s[i]=(s[i-1]+f[i])%mod; if(node[i].x==sx&&node[i].y==sy){printf("%d\n",f[i]);return 0;} } }
F.
DFS+贪心
//By SiriusRen #include <bits/stdc++.h> using namespace std; const int N=2000500; int n,k,xx,yy,first[N],nxt[N],v[N],tot,du[N],ans; void add(int x,int y){v[tot]=y,nxt[tot]=first[x],first[x]=tot++;} int dfs(int x,int fa){ if(du[x]==1)return 0; vector<int>vec; for(int i=first[x];~i;i=nxt[i])if(v[i]!=fa) vec.push_back(dfs(v[i],x)+1); sort(vec.begin(),vec.end()); for(int i=vec.size()-1;~i;i--){ int temp=vec[i]; if(i)temp+=vec[i-1]; if(temp<=k)return vec[i]; ans++; }return -1000000; } int main(){ memset(first,-1,sizeof(first)); scanf("%d%d",&n,&k); for(int i=1;i<n;i++){ scanf("%d%d",&xx,&yy); add(xx,yy),add(yy,xx); du[xx]++,du[yy]++; } for(int i=1;i<=n;i++)if(du[i]>1){if(dfs(i,-1)>0)ans++;break;} printf("%d\n",ans); }
