2020杭电多校第三场

1004.Tokitsukaze and Multiple

强大的队友构造出来的

#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long ll;
const int mod=1e9+7;
const int maxn=1e5+10;
int a[maxn],cnt;
ll s[maxn];
int t,n,p;
int main()
{
    cin>>t;
    while(t--)
    {
        scanf("%d %d",&n,&p);
        int k=0;
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&a[i]);
            s[i]=s[i-1]+a[i];
            if(s[i]<p)
                k=i;
        }
        int sum=0,m=0;
        for(k=k+1;k<=n;k++)
        {
            for(int i=m;i<k;i++)
            {
                if((s[k]-s[i])%p==0)
                {
                    sum++,m=k;
                    break;
                }
                else if(s[k]-s[i]<p)
                    break;
            }
        }
        printf("%d\n",sum);
    }
    return 0;
}

1005.Little W and Contest

并查集瞎搞

#include<bits/stdc++.h>
using namespace std;
const int N = 100000 + 5;
const int mod = (int)1e9 + 7;
long long t,a[N],b[N],r[N],n,s,fa[N];
int fin(int x)
{
    if(x==fa[x])
    {
        return x;
    }
    else
    {
        return fa[x]=fin(fa[x]);
    }
}
void mege(int x,int y)
{
    fa[fin(x)]=fin(y);
}
int main()
{
    cin>>t;
    while(t--)
    {
        cin>>n;
        s=0;
        for(int i=1;i<=n;i++)
        {
            cin>>a[i];
            if(a[i]==2)
                s++;
            fa[i]=i;
            if(a[i]==2)
            {
                b[i]=1;
                r[i]=0;
            }
            else
            {
                r[i]=1;
                b[i]=0;
            }

        }
        long long ans;
        ans=s*(s-1)*(n-s)/2+s*(s-1)*(s-2)/6;
        ans%=mod;
        cout<<ans<<endl;
        for(int i=1;i<=n-1;i++)
        {
            int u,v;
            cin>>u>>v;
            int p,q;
            p=fin(u);
            q=fin(v);
            if(p!=q)
            {
                int c=b[p],d=b[q],e=r[p],f=r[q];
                mege(u,v);
                b[fin(u)]=c+d;
                r[fin(u)]=e+f;
                ans-=c*d*(n-s-e-f)%mod+c*f*(s-c-d)%mod+d*e*(s-c-d)%mod+c*d*(s-c-d)%mod;
                ans%=mod;
                ans+=mod;
                ans%=mod;
            }
            cout<<ans<<endl;
        }
    }
    return 0;
}

1009.Parentheses Matching

贪心

#include<bits/stdc++.h>
using namespace std;
const int N = 100000 + 5;
const int mod = (int)1e9 + 7;
#define ll long long
#define endl '\n'
long long t,n,s,k[N],sum,l;
char a[N];
int main()
{
    std::ios::sync_with_stdio(false);
    cin>>t;
    while(t--)
    {
        cin>>a;
        n=strlen(a);
        s=0;
        l=0;
        sum=0;
        int flag=1;
        for(int i=0;i<n;i++)
        {
            if(a[i]=='*')
            {
                s++;
                k[s]=i;
            }
            else if(a[i]=='(')
            {
                sum++;
            }
            else
            {
                if(sum==0)
                {
                    l++;
                    if(l<=s)
                    a[k[l]]='(';
                    else
                    {
                        flag=0;
                        break;
                    }
                }
                else
                    sum--;
            }
        }
        if(flag==0)
            cout<<"No solution!"<<endl;
        else if(sum>s-l)
            cout<<"No solution!"<<endl;
        else
        {
            s=0;
            l=0;
            sum=0;
            flag=1;
            for(int i=n-1;i>=0;i--)
            {
                if(a[i]=='*')
                {
                    s++;
                    k[s]=i;
                }
                else if(a[i]==')')
                {
                    sum++;
                }
                else
                {
                    if(sum==0)
                    {
                        l++;
                        if(l<=s)
                        a[k[l]]=')';
                        else
                        {
                            flag=0;
                            break;
                        }
                    }
                    else
                        sum--;
                }
            }
            if(flag==0)
                cout<<"No solution!"<<endl;
            else
            {
                for(int i=0;i<n;i++)
                {
                    if(a[i]!='*')
                        cout<<a[i];
                }
                cout<<endl;
            }

        }

    }
    return 0;
}