清北刷题冲刺 10-31 p.m

数列

#include<iostream>
#include<cstdio>
using namespace std;
long long a,b,ans;
void f(long long x,long long y){
    if(y==0)return;
    ans+=x/y;
    f(y,x%y);
}
int main(){
    freopen("seq.in","r",stdin);freopen("seq.out","w",stdout);
    cin>>a>>b;
    ans=1;
    f(a,b);
    cout<<ans;
}

车辆销售

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#include<ctime>
#define maxn 100010
#ifdef WIN32
#define PLL "%I64d"
#else
#define PLL "%lld"
#endif
using namespace std;
int n,m,num,head[maxn],mx,mn=0x7fffffff,cnt;
bool vis[maxn];
struct node{
    int to,pre,v;
}e[200010*2];
void Insert(int from,int to,int v){
    e[++num].to=to;
    e[num].v=v;
    e[num].pre=head[from];
    head[from]=num;
}
int q[maxn],h,t;
int res;
bool flag=0,com[maxn];
int bfs(int limit){
    h=1;
    while(h<=t){
        int now=q[h];h++;
        if(com[now])continue;
        flag=0;
        for(int i=head[now];i;i=e[i].pre){
            if(e[i].v<limit){
                flag=1;
                continue;
            }
            int to=e[i].to;
            if(!vis[to]){
                res++;
                vis[to]=1;
                q[t++]=to;
            }
        }
        if(flag==0)com[now]=1;
    }
    return res;
}
int qread(){
    int i=0,j=1;
    char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')j=-1;ch=getchar();}
    while(ch<='9'&&ch>='0')i=i*10+ch-'0',ch=getchar();
    return i*j;
}
int main(){
//    freopen("Cola.txt","r",stdin);
    freopen("car.in","r",stdin);freopen("car.out","w",stdout);
    n=qread();m=qread();
    int x,y,z;
    for(int i=1;i<=m;i++){
        x=qread();y=qread();z=qread();
        Insert(x,y,z);Insert(y,x,z);
        mx=max(mx,z);mn=min(mn,z);
    }
    long long ans;
    for(int i=1;i<=n;i++){
        ans=0;
        memset(q,0,sizeof(q));h=t=1;
        memset(vis,0,sizeof(vis));
        memset(com,0,sizeof(com));
        q[t++]=i;vis[i]=1;
        res=0;
        int p,now;
        for(int j=mx+1;j>=mn-1;j--){
            if(j<0)break;
            now=bfs(j);
            if(j==mx+1){p=now;continue;}
            ans+=1LL*(p-now)*(p-now);
            p=now;
        }
        printf(PLL" ",ans);
    }
//    cout<<endl<<clock();
}

取数

#include<iostream>
#include<cstdio>
#define maxn 1000010
using namespace std;
int n,m,k,a[maxn];
long long ans=10000000000000;
int qread(){
    int i=0,j=1;
    char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')j=-1;ch=getchar();}
    while(ch<='9'&&ch>='0')i=i*10+ch-'0',ch=getchar();
    return i*j;
}
void dfs(int pos,int cnt,long long sum){
    if(cnt==k){
        ans=min(ans,sum);
        return;
    }
    if(sum>=ans)return;
    if(pos>=n)return;
    int res=0;
    res+=(n-pos)/m;
    if(res*m<n-pos)res++;
    if(res+cnt<k)return;
    if(cnt==0){
        for(int i=pos+1;i<=n;i++)dfs(i,cnt+1,sum+a[i]);
        return;
    }
    for(int i=pos+m;i<=n;i++){
        dfs(i,cnt+1,sum+a[i]);
    }
}
int main(){
    freopen("number.in","r",stdin);freopen("number.out","w",stdout);
//    freopen("Cola.txt","r",stdin);
    n=qread();m=qread();k=qread();
    for(int i=1;i<=n;i++)a[i]=qread();
    dfs(0,0,0);
    cout<<ans;
}

预计得分100+30+0
实际得分100+30+20
T1有一定的思维量，但是代码很好写，也很容易从辗转相减想到辗转相除。T2T3都写的暴力，T3用的dfs，写的剪枝比较多，所以得到了20分。
感觉这几天以来上午炸的概率比较大，精神状态不好，下午相对还可以。晚上要保证睡眠充足，尽量以较好的精神面貌迎接上午的考试