2018年全国多校算法寒假训练营练习比赛（第五场）

A    逆序数

归并求逆序数标打

 #include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int inf = 987654321;
const int sz = 1e6 + 5;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
int a[sz],t[sz];
ll n,sum;
 
void merge_func(int s1,int e1,int s2,int  e2)
{
    int p=s1,p1=s1,p2=s2;
    while(p1<=e1&&p2<=e2)
    {
        if(a[p1]<=a[p2]) t[p++]=a[p1++];
        else t[p++]=a[p2++],sum+=(e1-p1+1); 
    }
    while(p1<=e1) t[p++]=a[p1++];  
    while(p2<=e2)  t[p++]=a[p2++]; 
    f(i,s1,e2) a[i]=t[i]; 
}
void merge(ll l,ll r)
{
    if(l<r)
    {
        ll mid =(l+r)>>1;
        merge(l,mid);
        merge(mid+1,r);
        merge_func(l,mid,mid+1,r);
    } 
}
int main()
{
     
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    cin>>n;
    f(i,1,n)cin>>a[i]; 
    merge(1,n);
    cout<<sum<<endl;
    
    return 0; 
}

 

B    Big Water Problem    

　　维护一下前缀和就好了

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int inf = 987654321;
const int sz = 1e6 + 5;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
 int n,m;
 int a[sz];ll b[sz];
 ll s[sz];
int op,l,r;
int main()
{
     
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    cin>>n>>m;
    f(i,1,n)cin>>a[i],s[i]=s[i-1]+a[i];
    f(j,1,m)
    {
        cin>>op>>l>>r;
        if(op==1)
        {
            f(i,l,n)s[i]+=r;
        }
        else
        {
             
            cout<<s[r]-s[l-1]<<endl;
        }
    }
    
    return 0; 
}

 

 

C    字符串的问题

只过了50% ,没找到错误,帮我改一下 ,kmp 取一下nxt 数组 然后最后一个元素的大小 几位前缀后缀相同

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int inf = 987654321;
const int sz = 1e6 + 5;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
#define CLR(arr,val) memset(arr,val,sizeof(arr))
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
char a[sz];
int nxt[sz],nn[sz]; 
void getnxt()
{
    int i=0,len=strlen(a),k=-1;
    CLR(nxt,-1); 
    while(i<len)
    {
        if(k==-1||a[i]==a[k])
            nxt[++i]=++k;
        else k=nxt[k]; 
    } 
}
void kmp()
{
    getnxt();
    int len=strlen(a);
    int ans =nxt[len-1];
    if(ans==0)
    {
        cout<<"Just a legend"<<endl;
        return ;
    }
    bool flag =false;
    g(i,len-2,0)
        if(ans==nxt[i])
        {
            flag=true;
            break;
        }
    if(flag)f(i,0,ans)cout<<a[i];
    else     cout<<"Just a legend"<<endl;

//    f(i,0,len-1)cout<<nxt[i]<<" ";
 /*    f(i,0,len-1)ans=max(ans,nxt[i]);




     f(i,0,len-1) nn[nxt[i]]++;
     f(i,ans,1)
         if(nn[i]==2)break;
         else ans=i-1;
     if(ans<2)cout<<"Just a legend"<<endl;
     else cout<<ans<<endl;
*/
}
int main()
{
     FAST_IO ;
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    cin>>a;
    kmp();
     
    return 0; 
}

 

D    集合问题

求一下交并集 ,然后合并 一下就好了

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int inf = 987654321;
const int sz = 1e6 + 5;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
#define CLR(arr,val) memset(arr,val,sizeof(arr))
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
int n,a,b;
int p[sz],fa[sz];
map<int,int> m;

 
int Find(int x)
{
    int r=x,t;
    while(r!=fa[r])r=fa[r];
    while(x!=r)
    {
        t=fa[x];
        fa[x]=r;
        x=t;
    }
    return r;
}
 
  
void Union(int u,int v){
    int uu=Find(u);
    int vv=Find(v);
    if(uu!=vv)  fa[uu]=vv; 
}
void work()
{
    cin>>n>>a>>b;
    int mm=0;
    f(i,1,n)
    {
        cin>>p[i];
         m[p[i]]=i;
         mm = max(mm,p[i]);
     } 
    if(mm >max(a,b))
    {
        cout<<"NO"<<endl;
        return ;
    } 
    f(i,0,n+1)fa[i]=i;
    f(i,1,n)
    {
        if(m[a-p[i]])Union(i,m[a-p[i]]);
        else Union(i,n+1);
        if(m[b-p[i]])Union(i,m[b-p[i]]);
        else Union(i,0); 
    }
    int A =Find(0);
    int B = Find(n+1);
    if(A!=B)
    {
        cout<<"YES"<<endl;
        f(i,1,n)
        {
            if(i!=1) cout<<" ";
            if(Find(i)==A)cout<<0;
            else cout<<1; 
        } 
    }
    else cout<<"NO"<<endl;
    return ;
    
}
int main()
{
    FAST_IO ;
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    work();
    
    return 0; 
}

 

E    情人节的电灯泡

树状数组,直接报了的话 TLE

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int inf = 987654321;
const int sz = 1e4 + 5;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
#define CLR(arr,val) memset(arr,val,sizeof(arr))
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
#define pii pair<int,int>
#define lowbit(x) x&(-x)
#define X first
#define Y second
int n,m,op,s1,e1,s2,e2;
int bits[sz][sz],a[sz][sz];
void update(int l,int r,int k)
{
    for(int i=l;i<=n;i+=lowbit(i))
        for(int j=r;j<=n;j+=lowbit(j))
            bits[i][j]+=k;
}
int query(int l,int r)
{
    int ans=0;
    for(int i=l;i;i-=lowbit(i))
        for(int j=r;j;j-=lowbit(j))
            ans+=bits[i][j];
    return ans;
}
void work()
{
    cin>>n>>m;
    f(i,1,n)f(j,1,n)
    {
        cin>>a[i][j];
        if(a[i][j])update(i,j,1);
    }
    f(i,1,m)
    {
        cin>>op;
        if(op==1)
        {
            cin>>s1>>e1;
            int v=(a[s1][e1]^1)-a[s1][e1];
            a[s1][e1]^=1;
            update(s1,e1,v);
        }
        else
        {
            cin>>s1>>e1>>s2>>e2;
            cout<<query(s2,e2)-query(s1-1,e2)-query(s2,e1-1)+query(s1-1,e1-1)<<endl;
        }
    }

    
}
int main()
{
    FAST_IO ;
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    work();
    
    return 0; 
}

 

F    The Biggest Water Problem

斐波那契博弈论 ,斐波那契数列的数字都是输家

 

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int inf = 987654321;
const int sz = 1e6 + 5;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
#define CLR(arr,val) memset(arr,val,sizeof(arr))
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
#define pii pair<int,int>
#define lowbit(x) x&(-x)
#define X first
#define Y second
int calc(int n)
{
    if(n<10)return n;
    int ans = 0;
    while(n)
    {
        ans+=n%10;
        n/=10;
    }
    return calc(ans);
}

void work()
{
    int n;
    cin>>n;
    cout<<calc(n)<<endl;
    
}
int main()
{
    FAST_IO ;
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    work();
    cout<<"hello"<<endl;

    return 0; 
}

 

G    送分啦-QAQ

和前几天一场cf 题目一样

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int inf = 987654321;
const int sz = 1e6 + 5;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
#define CLR(arr,val) memset(arr,val,sizeof(arr))
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
#define pii pair<int,int>
#define lowbit(x) x&(-x)
#define X first
#define Y second

void work()
{
    int n,a=1,b=1,s;
    bool flag=false;
    cin>>n;
    while(a<n)
    {
        s=b;
        b=a+b;
        a=s;
    }
    if(a==n)cout<<"Sha"<<endl;
    else   cout<<"Xian"<<endl;
}
int main()
{
    FAST_IO ;
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    work();
   
    return 0; 
}

 

H    Tree Recovery

暴力了,乱搞出的

#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef double    dl ;
#define INF 0x7f

const int inf = 987654321;
const int sz = 1e6 + 5;
const int mod = 1e9 + 7;
const int sqrtn = 300;

#define f(i,l,r) for(int i=l;i<=r;++i)
#define g(i,l,r) for(int i=l;i>=r;--i)
#define CLR(arr,val) memset(arr,val,sizeof(arr))
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
#define pii pair<int,int>
#define lowbit(x) x&(-x)
#define X first
#define Y second
int calc(int n)
{
    if(n<10)return n;
    int ans = 0;
    while(n)
    {
        ans+=n%10;
        n/=10;
    }
    return calc(ans);
}

void work()
{
    int n;
    cin>>n;
    cout<<calc(n)<<endl;
    
}
int main()
{
    FAST_IO ;
    freopen("in","r",stdin);
    freopen("out","w",stdout);
    work();
    cout<<"hello"<<endl;

    return 0; 
}