牛客小白月赛12

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A华华听月月唱歌 (贪心)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=1e5+50;
const int inf=1e9;
typedef unsigned long long ull;
int n,m,tot;
struct node{
    int l,r;
}my[maxn];
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    cin>>m>>n;
    for(int i=1;i<=n;i++)cin>>my[i].l>>my[i].r;
    sort(my+1,my+1+n,[](node a,node b){
        return a.l<b.l;
    });
    int l=1,k=1;int ans=0;
    while(l<=m&&k<=n){
        int t=0;
        while(my[k].l<=l && k<=n)t=max(my[k].r,t),k++;
        l=t+1;ans++;
        if(t==0)k++;
    }
    if(l>m)cout<<ans<<endl;
    else cout<<-1<<endl;
    return 0;
}

B.华华教月月做数学 (快速幂+龟速乘)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=1e5+50;
const int inf=1e9;
typedef unsigned long long ull;
ll a,b,p;
ll gw(ll a,ll b){
    ll ret=0;
    while(b){
        if(b&1)ret=(ret+a)%p;
        b>>=1;
        a=(a+a)%p;
    }
    return ret;
}
ll pw(ll a,ll b){
    ll ret=1;
    while(b){
        if(b&1)ret=gw(ret,a);
        a=gw(a,a);b>>=1;
    }
    return ret;
}
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    int t;
    cin>>t;
    while(t--){
        cin>>a>>b>>p;
        cout<<pw(a,b)<<endl;
    }
    return 0;
}

C.华华给月月出题 (线性筛 极性函数)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=2e7+50;
const int inf=1e9;
typedef unsigned long long ull;

ll value[maxn];
bool check[maxn];
ll prime[maxn];

ll pw(ll a,ll n){
    ll ans=1;
    while(n){
        if(n&1)ans=(1LL*ans*a)%mod;
        a=(a*a)%mod;
        n>>=1;
    }
    return ans;
}
ll getvalue(ll n){
    value[1]=1;
    int tot=0;
    for(ll i=2;i<=n;i++){
        if(!check[i]){
            value[i]=1LL*pw(1LL*i,1LL*n);
            prime[tot++]=i;
        }
        for(ll j=0;j<tot;j++){
            if(1LL*i*prime[j]>n)break;
            check[i*prime[j]]=true;
            value[i*prime[j]]=1LL*value[i]*value[prime[j]]%mod;
            if(i%prime[j]==0)break;
           /* else{
                value[i*prime[j]]=1LL*value[i]*value[prime[j]]%mod;
            }*/
        }
    }
    ll ans=0;
    for(int i=1;i<=n;i++)ans=(1LL*ans^value[i]);
    return ans;
}
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    ll n;
    cin>>n;
    cout<<getvalue(n);
    return 0;
}

D.月月给华华出题 (线性筛欧拉函数)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=1e6+50;
const int inf=1e9;
typedef unsigned long long ull;
bool check[maxn];
int phi[maxn];
int prime[maxn];
int tot;
void phi_and_prime_table(int N){
    phi[1]=1;
    for(int i=2;i<=N;i++){
        if(!check[i]){
            prime[tot++]=i;
            phi[i]=i-1;
        }
        for(int j=0;j<tot;j++){
            if(i*prime[j]>N)break;
            check[i*prime[j]]=true;
            if(i%prime[j]==0){
                phi[i*prime[j]]=phi[i]*prime[j];
                break;
            }
            else{
                phi[i*prime[j]]=phi[i]*(prime[j]-1);
            }
        }
    }

}
ll ans[maxn];
ll cal(int n){
    return 1LL*n*phi[n]/2+(n==1);
}
int main()
{
    /*std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);*/
    int n;
    scanf("%d",&n);
    phi_and_prime_table(n);
    for(int i=1;i<=n;i++){
        for(int j=i;j<=n;j+=i)ans[j]+=cal(j/i);
    }
    for(int i=1;i<=n;i++)
        printf("%lld\n",ans[i]);
    return 0;
}

E.华华给月月准备礼物 (二分)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=2e5+50;
const int inf=1e9;
typedef unsigned long long ull;
int a[maxn];
int n,k;
bool ok(int mid){
    int ans=0;
    for(int i=1;i<=n;i++){
        ans+=a[i]/mid;
    }
    if(ans>=k)return true;
    else return false;
}
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    cin>>n>>k;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    int l=1,r=1e9+1,ans=0;
    while(l<=r){
        int mid=(l+r)/2;
        if(ok(mid)){
            ans=mid,l=mid+1;
        }
        else r=mid-1;
    }
    cout<<ans<<endl;
    return 0;
}

F.华华开始学信息学 (分类讨论+树状数组)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=1e5+50;
const int inf=1e9;
typedef unsigned long long ull;

ll lazy[maxn];
ll sum[maxn];
int block;
void update(int x,int val){
    while(x<maxn){
        sum[x]+=val;
        x+=(x&(-x));
    }
}
ll query(int x){
    ll ans=0;
    while(x){
        ans+=sum[x];
        x-=(x&(-x));
    }
    return ans;
}
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    int n,m;
    cin>>n>>m;
    block=sqrt(n);
    int op,a,b;
    while(m--){
        cin>>op>>a>>b;
        if(op==1){
            if(a>block){
                for(int i=a;i<=n;i+=a)update(i,b);
            }
            else lazy[a]+=b;
        }
        else{
            ll ans=query(b)-query(a-1);
            for(int i=1;i<=block;i++){
                ans+=(b/i-(a-1)/i)*lazy[i];
            }
            cout<<ans<<endl;
        }
    }
    return 0;
}

G.华华对月月的忠诚 (思维)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=1e5+50;
const int inf=1e9;
typedef unsigned long long ull;


int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    ll a,b;
    string n;
    cin>>a>>b>>n;
    cout<<__gcd(a,b);

    return 0;
}

H.华华和月月种树 (树状数组)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=5e5+50;
const int inf=1e9;
typedef unsigned long long ull;

ll sum[maxn],cnt,sz[maxn],id[maxn];
void update(int x,int val){
    while(x<maxn){
        sum[x]+=val;
        x+=(x&(-x));
    }
}
ll query(int x){
    ll ans=0;
    while(x){
        ans+=sum[x];
        x-=(x&(-x));
    }
    return ans;
}
struct node{
    int a,b,c;
}my[maxn];
vector<int>G[maxn];
void add(int u,int v){
    G[u].push_back(v);
    G[v].push_back(u);
}
void dfs(int now,int pre){
    sz[now]=1;
    id[now]=++cnt;
    for(auto i:G[now]){
        if(i==pre)continue;
        dfs(i,now);
        sz[now]+=sz[i];
    }
}
int n;
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    int m;
    cin>>m;
    for(int i=1;i<=m;i++){
        cin>>my[i].a>>my[i].b;
        if(my[i].a==1){
            n++;
            add(my[i].b,n);
        }
        if(my[i].a==2)cin>>my[i].c;
    }
    dfs(0,-1);
    int res=0;
    for(int i=1;i<=m;i++){
        if(my[i].a==1){
            res++;
            int x=query(id[res]);
            update(id[res],-x);
            update(id[res]+sz[res],x);
        }
        else if(my[i].a==2){
            update(id[my[i].b],my[i].c);
            update(id[my[i].b]+sz[my[i].b],-my[i].c);
        }
        else cout<<query(id[my[i].b])<<endl;
    }
    return 0;
}

I.华华和月月逛公园 (求桥)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=1e5+50;
const int inf=1e9;
typedef unsigned long long ull;

struct Edge{
    int u,v;
};
///割顶 bccno 无意义
int pre[maxn],iscut[maxn],bccno[maxn],dfs_clock,bcc_cut;
vector<int>G[maxn],bcc[maxn];
stack<Edge>S;
void init(int n){
    for (int i = 0; i < n; i++) G[i].clear();
}
int lowu[maxn];
int father[maxn];
inline void add_edge(int u, int v) { G[u].push_back(v), G[v].push_back(u); }
void dfs(int u,int fa){
    lowu[u] = pre[u] = dfs_clock++;
    father[u]=fa;
    int child = 0;
    for(int i = 0; i < G[u].size(); i++){
        int v =G[u][i];
        if(pre[v]==-1){
            dfs(v,u);
            lowu[u]=min(lowu[u],lowu[v]);
        }
        else if(v!=fa){
            lowu[u]=min(lowu[u],pre[v]);
        }
    }
}

int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=m;i++){
        int u,v;
        cin>>u>>v;
        add_edge(u,v);
    }
    memset(pre,-1,sizeof(pre));
    memset(lowu,-1,sizeof(lowu));
    dfs(1,-0);
    int sum=0;
    for(int i=1;i<=n;i++){
        int v=father[i];
        if(v>0&&lowu[i]>pre[v])sum++;
    }
    cout<<m-sum<<endl;
    return 0;
}

J. 月月查华华的手机 (贪心)

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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
const int maxn=1e6+50;
const int inf=1e9;
typedef unsigned long long ull;
int go[maxn][30];
char s[maxn];
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    cin>>s;
    int len=strlen(s);
    for(int i=0;i<26;i++){
        go[len][i]=-1;
    }
    for(int i=len-1;i>=0;i--){
        for(int j=0;j<26;j++){
            if(s[i]==char('a'+j)){
                go[i][j]=i+1;
            }
            else
                go[i][j]=go[i+1][j];
        }
    }
   /* for(int i=0;i<26;i++){
        cout<<char('a'+i)<<" ";
    }
    cout<<endl;
    for(int i=0;i<=len;i++){
        for(int j=0;j<26;j++){
            cout<<go[i][j]<<" ";
        }
        cout<<endl;
    }*/
    int m;
    cin>>m;
    while(m--){
        cin>>s;
        len=strlen(s);
        int now=0,flag=0;
        for(int i=0;i<len;i++){
            now=go[now][s[i]-'a'];
            if(now==-1){
                flag=1;break;
            }
          //  cout<<"i="<<i<<" now="<<now<<endl;
        }
        if(flag)cout<<"No"<<endl;
        else cout<<"Yes"<<endl;
    }
    return 0;
}