从本地服务入手做本地网站/重庆seo网页优化

题目链接

A.校园活动

思路：

爆搜，枚举对象：一个小组内所有人对游戏的了解程度之和。之后判断每个方案，在可行前提下的组数，取min即可

#include <iostream>
#include<bits/stdc++.h>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <queue>
#include <cstring>
#include <set>
#include <map>
#include <sstream>
#define LL long long
#define mem(f, x) memset(f,x,sizeof(f)) 
#define fo(i,a,n) for(int i=a;i<n;++i)
#define foo(i,a,n) for(int i=a;i<=n;++i)
const int INF = 0x3f3f3f3f;
using namespace std;
template<class T>inline void read(T &x){x=0; char c=getchar(); bool f=0;while(!isdigit(c))f^=c=='-',c=getchar();while(isdigit(c))x=(x<<3)+(x<<1)+(c^48),c=getchar();if(f)x=-x;
}
int a[1005];
int n;
int check(int t){int k=t,sum=0;for(int i=0;i<n;i++){if(k>a[i])k-=a[i];else if(k==a[i])k=t,sum++;else return -1;}return sum;
}
int main(){int sum=0,k=1;cin>>n;getchar();fo(i,0,n){a[i]=getchar();a[i]-='0';sum+=a[i];}	for(int i=0;i<=sum;i++){if(i && sum%i)continue;k=max(check(i),k);}if(k==1)cout<<"-1";else cout<<k;return 0;
}

C.CG的通关秘籍

注：在$m\ast (m-1)$处除以2也可以，就不用逆元了

#include <iostream>
#include<bits/stdc++.h>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <queue>
#include <cstring>
#include <set>
#include <map>
#include <sstream>
#define LL long long
#define ll long long
#define mem(f, x) memset(f,x,sizeof(f)) 
#define fo(i,a,n) for(int i=a;i<n;++i)
#define foo(i,a,n) for(int i=a;i<=n;++i)
const int INF = 0x3f3f3f3f;
using namespace std;
LL powmod(LL a,LL b,LL MOD){LL ans=1;while(b){if(b%2)ans=ans*a%MOD;a=a*a%MOD;b/=2;}return ans;
}
inline ll inv(ll x,ll p){return powmod(x,p-2,p);}
template<class T>inline void read(T &x){x=0; char c=getchar(); bool f=0;while(!isdigit(c))f^=c=='-',c=getchar();while(isdigit(c))x=(x<<3)+(x<<1)+(c^48),c=getchar();if(f)x=-x;
}
template<class T>inline void print(T x){if(x<0)putchar('-'),x=-x;if(x>9)print(x/10);putchar('0'+x%10);
}
const LL mod=1e9+7;
int main(){int t;cin>>t;LL n,m;while(t--){read(n);read(m);LL sum=powmod(m,n-2,mod)*(n-1)%mod;LL k=(3*m*m-3*m)%mod;sum=inv(2,mod)*sum%mod*k%mod;print(sum);printf("\n");}
}