清北刷题冲刺 10-31 a.m
集合
#include<iostream> #include<cstdio> #include<algorithm> using namespace std; int n,a[1000010],cnt; int main(){ freopen("multiset.in","r",stdin);freopen("multiset.out","w",stdout); // freopen("Cola.txt","r",stdin); scanf("%d",&n); for(int i=1;i<=n;i++)scanf("%d",&a[i]); if(n==1&&a[1]==0){ puts("0"); return 0; } int ans=0; sort(a+1,a+n+1); int q=1; for(int i=1;i<=n;i++){ if(a[i]!=0){q=i;break;} cnt++; } while(1){ if(q>n)break; ans++;cnt=cnt/2+cnt%2; for(int i=q;i<=n;i++)a[i]-=1; // for(int i=1;i<=n;i++)cout<<a[i]<<' '; while(a[q]==0&&q<=n)cnt++,q++; } while(cnt>1){ ans++; cnt=cnt/2+cnt%2; } printf("%d",ans); }
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #define maxn 1000010 using namespace std; int n,a[maxn],cnt[maxn],res,lim; int main(){ freopen("multiset.in","r",stdin); freopen("multiset.out","w",stdout); scanf("%d",&n); for(int i=1;i<=n;i++){ scanf("%d",&a[i]); lim=max(lim,a[i]); cnt[a[i]]++; } int l=0,z=cnt[0]; for(int i=1;i<=lim;i++){ res++; z=(z+1)/2; z+=cnt[i]; } for(;z>1;z=(z+1)/2)res++; printf("%d",res); return 0; }
道路分组
#include<iostream> #include<cstdio> #include<vector> #include<cstring> #include<algorithm> #define maxn 100010 #define maxm 500010 using namespace std; int n,m,num,head[maxn],mid; int q[maxm],q1[maxm],cnt; vector<int>road[500010]; struct node{ int to,pre,id; }e[maxm]; struct Node{ int l,r; }jian[maxm]; void Insert(int from,int to){ e[++num].to=to; e[num].id=num; e[num].pre=head[from]; head[from]=num; } bool vis[maxm]; void dfs(int pos,int c){ if(pos==n){ cnt++; jian[cnt].l=0x7fffffff; for(int i=1;i<c;i++){ road[cnt].push_back(q[i]); jian[cnt].l=min(jian[cnt].l,q[i]); jian[cnt].r=max(jian[cnt].r,q[i]); } return; } for(int i=head[pos];i;i=e[i].pre){ int to=e[i].to; if(!vis[to]){ q[c]=i; vis[to]=1; dfs(to,c+1); vis[to]=0; } } } bool cmp(Node x,Node y){return x.l<y.l;} int main(){ freopen("road.in","r",stdin);freopen("road.out","w",stdout); // freopen("Cola.txt","r",stdin); scanf("%d%d",&n,&m); int x,y; for(int i=1;i<=m;i++){ scanf("%d%d",&x,&y); Insert(x,y); } vis[1]=1; dfs(1,1); memset(vis,0,sizeof(vis)); sort(jian+1,jian+cnt+1,cmp); int ans=1; int L=0,R=0x7fffffff; int last=0; for(int i=1;i<=cnt;i++){ L=max(L,jian[i].l); R=min(R,jian[i].r); if(L>=R){ // if(!flag)flag=1,ans+=2; // else ans+=1; ans+=2; L=0;R=0x7fffffff; last=i; } } if(last!=cnt)ans++; printf("%d",ans); return 0; }
#include<iostream> #include<cstdio> #include<cstdlib> #include<algorithm> #include<vector> #define maxn 500010 using namespace std; int n,m,vis[maxn],x[maxn],y[maxn]; vector<int>vec[maxn]; bool dfs(int u){ if(vis[u])return false; if(u==n)return true; vis[u]=1; bool ret=false; for(int i=0;i<vec[u].size();i++){ ret=dfs(vec[u][i]); if(ret)return true; } return false; } bool check(int sta,int las){//检验sta~las的边能（0）否（1）在同一组内 for(int i=sta;i<=las;i++) vec[x[i]].push_back(y[i]); bool ret=dfs(1); for(int i=sta;i<=las;i++){ vis[x[i]]=vis[y[i]]=0; vec[x[i]].clear(); } vis[1]=0; return ret; } int main(){ freopen("road.in","r",stdin);freopen("road.out","w",stdout); scanf("%d%d",&n,&m); for(int i=0;i<m;i++)scanf("%d%d",&x[i],&y[i]); int now=0,ans=0; while(now<m){ int i; for(i=1;i+now<=m;i<<=1) if(check(now,now+i-1))break; i>>=1; int nowtmp=now+i; for(;i>0;i>>=1) if(nowtmp+i<=m&&!check(now,nowtmp+i-1)) nowtmp+=i; ans++;now=nowtmp; } cout<<ans; }
补兵
#include<iostream> #include<cstdio> #include<algorithm> #define maxn 1010 using namespace std; int T,n,a[maxn]; int main(){ freopen("cs.in","r",stdin);freopen("cs.out","w",stdout); // freopen("Cola.txt","r",stdin); scanf("%d",&T); while(T--){ scanf("%d",&n); for(int i=1;i<=n;i++)scanf("%d",&a[i]); sort(a+1,a+n+1); int p=1,ans=0; while(1){ if(a[p]==2&&p!=n){ a[p+1]-=2; a[p]-=1; for(int i=p+2;i<=n;i++)a[i]-=1; sort(a+1,a+n+1); } else{ a[p]-=2; if(a[p]==-1)ans++; for(int i=p+1;i<=n;i++)a[i]-=1; } while(a[p]<=0)p+=1; if(p>n)break; } printf("%d\n",ans); } }
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #define maxn 1010 using namespace std; int a[maxn],cnt[maxn],sta[maxn],c[maxn],f[maxn][maxn]; int main(){ freopen("cs.in","r",stdin);freopen("cs.out","w",stdout); int T; scanf("%d",&T); while(T--){ int n,mxn=0; scanf("%d",&n); memset(cnt,0,sizeof(cnt)); memset(c,0,sizeof(c)); memset(f,0,sizeof(f)); for(int i=1;i<=n;i++){ scanf("%d",&a[i]); ++cnt[a[i]]; mxn=max(mxn,a[i]); } int top=0; for(int i=1;i<=mxn;i++) if(cnt[i]==0)sta[++top]=i; else{ while(cnt[i]>1&&top>0){ c[sta[top--]]=i; --cnt[i]; } c[i]=i; } int ans=0; for(int i=1;i<=mxn;i++){ for(int j=0;j<=i;j++){ if(j>0)f[i][j]=f[i-1][j-1]; if(c[i]!=0&&j+c[i]-i<i) f[i][j]=max(f[i][j],f[i-1][j+c[i]-i]+1); ans=max(ans,f[i][j]); } } printf("%d\n",ans); } return 0; }
预计得分0+30+玄学 实际得分50+20+0 今天上午的题风格很奇怪，感觉暴力很难打，T1一开始没有思路，后来瞎几把乱打得了50。T2写了非常裸的暴力，T3没有思路，就贪心写了写。 这套题比较锻炼暴力能力，对思维的挑战也比较大，但是T2暴力得的分有点少，改题的时候要看看暴力怎么优化
