欢乐纪中A组赛【2019.8.18】

前言

有一个暴力写挂了 $Q V Q$

成绩

$R a n k$	$P e r s o n$	$S c o r e$	$A$	$B$	$C$
$11$	$(J - 3) L R Z$	$140$	$100$	$30$	$10$
$19$	$(J - 3) W Y C$	$120$	$100$	$10$	$10$
$26$	$(J - 3) H Z B$	$100$	$60$	$30$	$10$
$26$	$(J - 3) X J Q$	$100$	$100$	$0$	$0$
$39$	$(H - 1) Q Y H$	$90$	$20$	$70$	$0$
$39$	$(J - 3) X X Y$	$90$	$60$	$30$	$0$
$47$	$(J - 3) L W$	$70$	$40$	$30$	$0$
$60$	$(H - 2) H J W$	$40$	$40$	$0$	$0$
$60$	$(H - 2) L Z X$	$40$	$40$	$0$	$0$
$60$	$(H - 2) T R X$	$40$	$40$	$0$	$0$
$60$	$(J - 3) H J Q$	$40$	$40$	$0$	$0$

正题

$T 1 : j z o j 6309 -$ 完全背包【贪心 $,$ 背包】

链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/99707673

$T 2 : j z o j 6308 -$ 中间值【分治】

链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/99707694

$T 3 : j z o j 6306 - S e q u e n c e$ 【线性筛 $,$ 积性函数 $,$ 数论】

链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/99707865

总结

不想写，反正就是 $T 1$ 写了贪心 $T 2$ 写了暴力结果写挂了 $T 3$ 写了暴力 $10 p t s$

$SomeofcodeSome\ of\ code$

$T210ptscodeT2\ 10pts\ code$

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N=510000;
int n,m,a[N],b[N];
int calc(int *a,int w,int l,int r)
{return (lower_bound(a+l,a+1+r,w)-a)-l;}
int solve(int *a,int *b,int l1,int r1,int l2,int r2)
{int l=l1,r=r1,k=(r1-l1+r2-l2+3)/2;while(l<=r){int mId=(l+r)/2;if(mId-l1+1+calc(b,a[mId],l2,r2)<k) l=mId+1;else r=mId-1;}if(l>r1) return 0;return a[l]*((l-l1+1+calc(b,a[l],l2,r2))==k);
}
int main()
{freopen("median.in","r",stdin);freopen("median.out","w",stdout);scanf("%d%d",&n,&m);for(int i=1;i<=n;i++)scanf("%d",&a[i]);for(int i=1;i<=n;i++)scanf("%d",&b[i]);while(m--){int opt,x,y,l,r;scanf("%d%d%d%d",&opt,&x,&y,&l);if(opt==1){if(l) a[x]=y;else b[x]=y; }else{scanf("%d",&r);printf("%d\n",solve(a,b,x,y,l,r)|solve(b,a,l,r,x,y));}}
}

$T310ptscodeT3\ 10pts\ code$

#include<cstdio>
#include<cstring>
#include<algorithm>
const int XJQ=998244353;
int n,m,B,prime[5100000],cnt,ans;
bool v[21000000];
using namespace std;
int power(int x,int b)
{int ans=1;while(b){if(b&1) ans=ans*x%XJQ;x=x*x%XJQ;b>>=1;}return ans;
}
void dfs(int dep,int sum,int e)
{int i=1,k=0;if(dep>cnt){(ans+=power(sum,n))%=XJQ;return;}while(e*i<=m)dfs(dep+1,sum*(k+1),e*i),k++,i*=prime[dep];
}
void solve(int x,int gcd)
{if(x==n){(ans+=gcd)%=XJQ;return;}for(int i=1;i<=cnt;i++)solve(x+1,__gcd(gcd,prime[i]));
}
int main()
{freopen("sequence.in","r",stdin);freopen("sequence.out","w",stdout);scanf("%d%d%d",&n,&m,&B);if(B==1){v[1]=1;for(int i=2;i<=m;i++){if(!v[i]) prime[++cnt]=i;for(int j=1;j<=cnt&&i*prime[j]<=m;j++){v[prime[j]*i]=1;if(!(i%prime[j])) break;}}memset(v,0,sizeof(v));dfs(1,1,1);printf("%d",ans);}else{do{cnt=0;for(int i=1;i*i<=m;i++){if(!(m%i)) prime[++cnt]=i;if(!(m%i)&&m/i!=i)prime[++cnt]=m/i;}solve(0,B);}while(m--);printf("%d",ans);}
}