前言

有回来做$B$组了，话说第3道题就是$A$组第一道。

---

成绩

$Rank$是有算别人的
今天$XJQ$不在

$Rank$	$Person$	$Score$	$A$	$B$	$C$
$1$	$2017wyc$	$270$	$100$	$100$	$70$
$10$	$2017hjq$	$130$	$100$	$30$	$0$
$10$	$2017zyc$	$130$	$100$	$30$	$0$
$16$	$2017xxy$	$120$	$100$	$20$	$0$
$39$	$2017lw$	$30$	$0$	$30$	$0$
$46$	$2017hzb$	$20$	$0$	$20$	$0$
$46$	$2017lrz$	$20$	$0$	$20$	$0$

---

正题

---

$T1:jzoj4229-$学习神技【逆元$,$费马小定理】

博客链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/86561722

---

$T2:jzoj4230-$淬炼神体【$0/1$分数规划】

博客链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/86561780

---

$T3:jzoj4231-$寻找神格【线段树$,$数学】

神TM这道题有SPJ，让我输出3位小数，输出到10位就过了
誓死力争，还我AK!
博客链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/86561899

---

$someofcode$

---

T2暴力

#include<cstdio>
#include<algorithm>
using namespace std;
int n,k,a[16],b[16];
double ans;
int v[16];
double check()
{int sum_a=0,sum_b=0;for(int i=1;i<=n;i++)if(v[i]) sum_a+=a[i],sum_b+=b[i];return (double)sum_a/sum_b;
}
void dfs(int dep,int c){if(c==k){ans=max(check(),ans);if(ans>=2000)ans++,ans--;check();return;}if(dep>n) return;v[dep]=1;dfs(dep+1,c+1);v[dep]=0;dfs(dep+1,c);
}
int main()
{freopen("data.in","r",stdin);freopen("data.anss","w",stdout);scanf("%d%d",&n,&k);for(int i=1;i<=n;i++)scanf("%d",&a[i]);for(int i=1;i<=n;i++)scanf("%d",&b[i]);dfs(1,0);printf("%0.3lf",ans);
}

---

T2随机数据

#include<cstdlib>
#include<algorithm>
#include<cstdio>
#include<ctime>
#define random(x) rand()%x+1
using namespace std;
int main()
{freopen("data.in","w",stdout);srand(time(0));printf("15 %d\n",random(15));for(int i=1;i<=15;i++)printf("%d ",random(1000));printf("\n");for(int i=1;i<=15;i++)printf("%d ",random(1000));
}

---

T3暴力

#include<cstdio>
#define ll long long
using namespace std;
ll n,m,p[5010];
int main()
{//freopen("data.in","r",stdin);//freopen("data.ans","w",stdout);scanf("%lld%lld",&n,&m);for(ll i=1;i<=n;i++)scanf("%lld",&p[i]);for(ll i=1;i<=m;i++){ll t,a,b;scanf("%lld%lld%lld",&t,&a,&b);if(t==0) p[a]+=b;else if(t==1){ll z;scanf("%lld",&z);for(ll i=a;i<=b;i++)p[i]+=z;}else if(t==2){ll ans=0;for(ll i=a;i<=b;i++)ans+=p[i];printf("%lld\n",ans);}else{double n=(b-a+1),ans=0,sum=0;for(ll i=a;i<=b;i++)sum+=p[i];sum/=n;for(ll i=a;i<=b;i++)ans+=(double(p[i])-sum)*(double(p[i])-sum);ans/=n;printf("%0.3lf\n",ans);}}
}

---

T3随机数据

#include<cstdio>
#include<ctime>
#include<cstdlib>
#include<algorithm>
using namespace std;
int n,m,k;
int main()
{srand(time(0));//freopen("data.in","w",stdout);n=5;m=5;k=10;printf("%d %d\n",n,m);for(int i=1;i<=n;i++)printf("%d ",rand()%k*2-k);printf("\n");for(int i=1;i<=n;i++){int t=rand()%4,a=rand()%n+1,b=rand()%n+1;printf("%d ",t);if(a>b) swap(a,b);if(t==0)printf("%d %d\n",a,rand()%k*2-k);else if(t==1) printf("%d %d %d\n",a,b,rand()%k*2-k);else if(t==2)printf("%d %d\n",a,b);else printf("%d %d\n",a,b);}
}

---

尾声

誓死力争，还我AK!