Winter Camp 1

#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
const ll mod = 1000000007;
ll n,m;
int main()
{
    cin>>n>>m;
    ll a = (m-1)%mod*m%mod*(n-2)%mod*2%mod;
    ll b = (m-2)%mod*m%mod*(n-1)%mod*2%mod;
    ll c = (n-1)%mod*n%mod*(m-2)%mod*2%mod;
    ll d = (n-2)%mod*n%mod*(m-1)%mod*2%mod;
    //ll re1 = (m-2)%mod*(n-1)%mod*4%mod;
    //ll re2 = (n-2)%mod*(m-1)%mod*4%mod;
    //ll re = (re1+re2)%mod;
    ll sum = (a+b+c+d)%mod;
    //sum = (sum-re)%mod;
    cout<<sum<<endl;
    //cout<<(a%mod+b%mod+c%mod+d%mod-re1%mod-re2%mod)%mod<<endl;
    system("pause");

    return 0;
}

#include<iostream>
#include<cstdlib>
using namespace std;
typedef long long ll;
int main()
{
    //ios::sync_with_stdio(false);
    //cin.tie(NULL);
    //cout.tie(NULL);
    double n,x,a,b;
    cin>>n>>x>>a>>b;
    double ans = a*x/100.0+b-b*x/100.0;
    ans = ans * n;
    printf("%.2f\n",ans);
    system("pause");
    return 0;
    
}

#include<iostream>
#include<cstdlib>
#include<cstring>
using namespace std;
typedef long long ll;
ll n;
ll a[100001];
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    cin>>n;
    //memset(a,0,sizeof(a));
    for(ll i = 1;i<n;++i)
    {
        int x;
        cin>>x;
        a[x]++;
    }
    ll flag ;
    for(ll i=1;i<=n;++i)
    {
        if(a[i]==0)
        {
            flag = i;
            break;
        }
    }
    cout<<flag<<endl;
    //system("pause");
    return 0;
    
}

#include<iostream>
using namespace std;
typedef long long ll;
ll n;
ll count(ll n)
{
    ll s = 1;
    for(ll i =2;i*i <= n;++i)
    {
        if(n%i==0)
        {
            ll a = 0;
            while(n%i==0)
            {
                n = n/i;
                a++;
            }
            s = s*(a+1);
        }
    }
    if(n>1) s = s * 2;
    return s;
}
int main()
{
    cin>>n;
    ll num = 1;
    while(count(n)!=2)
    {
        n = count(n);
        num++;
    }
    cout<<num<<endl;
    system("pause");
    return 0;
}

#include<iostream>
#include<cstdlib>
#include<string>
#include<algorithm>
using namespace std;
typedef long long ll;
#define INF 0x3f3f3f3f
ll n,k;

int main()
{
	cin>>n>>k;
	string s;
	cin>>s;
	
	
	int l,r,ans;
    ans = INF;
	int a[100]={0};
	l = r = 0;
	while(r<s.size())
	{
		a[s[r]-'a']++;
		while(a[s[r]-'a']>=k)
		{
			ans = min(ans,r-l+1);
			
			a[s[l]-'a']-=1;
			l++;
		} 
		r++;
	}
	if(ans==INF)	
		cout<<-1<<endl;
    else
		cout<<ans<<endl;

	system("pause");
	return 0;
}

#include<bits/stdc++.h>
typedef long long ll;

using namespace std;
int a[200009];
int n,k;
bool check(int x)
{
    for(int i=x;i<=n;i++)
    {
        int ans = a[i]-a[i-x];//求零的数量也就是操作次数
        if(ans<=k||x-ans<=k)//如果0的数量比K小，那就在区间的右侧；
            return 1;
    }
    return 0;//否则在区间左侧 
}
int main()
{
    cin >> n >> k;
    string s;
    cin>>s;
    a[1] = s[0]-'0';
    /*前缀和*/
    for(int i=1;i<n;++i)
    {
        a[i+1]=a[i]+s[i]-'0';
        //cout<<a[i]<<endl;
    }
    /*二分*/
    int l = 1,r = n,mid;
    while(l<=r)
    {
        mid = (l+r)>>1;
        if(check(mid))
        {
            if(!check(mid+1))
                break;
            l = mid+1;
        }
        else 
            r = mid-1;
    }
    cout << mid <<endl;
    system("pause");
    return 0;
}