哈尔滨理工大学第七届程序设计竞赛决赛（网络赛-高年级组）（重现赛）

比赛地址
A
思路：思维规律题

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>

using namespace std;

typedef long long ll;
const ll mod=1e9+7;

/*ll quick_mul(ll x,ll y)
{
    ll ans=0;
    while(y){
        if(y&1)ans=(ans+x)%mod;
        x=(x+x)%mod;
        y>>=1;
    }
    return ans%mod;
}*/

int main()
{
    int n;
    while(~scanf("%d",&n)){
        ll ans=1;
        int a,b;
        for(int i=1;i<=n;i++){
            scanf("%d%d",&a,&b);
            ans=ans*(a+b)%mod;
        }
        printf("%lld\n",ans%mod);
    }
    return 0;
}

B
思路：枚举和暴力

#include<iostream>
#include<cstring>
#include<algorithm>
#include<string>

using namespace std;

typedef long long ll;

int main()
{
    int t;
    cin>>t;
    for(int kase=1;kase<=t;kase++){
        int k;
        cin>>k;
        string s;
        cin>>s;
        ll ans=0;
        for(int i=0;i+k<=s.length();i++){
            ll r=1,sum=0;
            for(int j=i+k-1;j>=i;j--){
                if(s[j]=='1')sum+=r;
                r*=2;
            }
            ans=max(ans,sum);
        }
        cout<<"Case #"<<kase<<": "<<ans<<endl;
    }
    return 0;
}

C
思路：dp

#include<iostream>
#include<cstring>
#include<string>
#include<algorithm>

using namespace std;

typedef long long ll;
const int N=1e5+10;
ll dp[N],w[N],v[N];


int main()
{
    ll t;
    while(~scanf("%lld",&t)){
        ll l,r,temp,A;
        memset(w,0,sizeof(w));
        memset(v,0,sizeof(v));
        memset(dp,0,sizeof(dp));
        for(int i=0;i<3;i++)scanf("%lld%lld",&w[i],&v[i]);
        scanf("%lld%lld%lld%lld",&l,&r,&temp,&A);
        w[3]=l,w[4]=r;
        v[3]=temp,v[4]=temp+(r-l)*A;
        for(int i=0;i<5;i++){
            for(int j=w[i];j<=t;j++){
                dp[j]=max(dp[j],dp[j-w[i]]+v[i]);
            }
        }
        for(ll i=l;i<=r;i++){
            dp[t]=max(dp[t],dp[t-i]+temp+(i-l)*A);
        }
        printf("%lld\n",dp[t]);
    }
    return 0;
}

G 幼儿园的战争
ps：因为这题我觉得可以单独写一篇题解，所以这里只贴一下代码，题解在这里

#include<iostream>
#include<cstring>
#include<string>
#include<algorithm>

using namespace std;

const int N=1e5+10;
int root[3*N],num[3*N],id[3*N];
int cnt,ans;

void Init(int n)
{
    cnt=n,ans=n;
    for(int i=1;i<=3*n;i++){
        root[i]=i;
        num[i]=1;
        id[i]=i;
    }
}

int Find(int x)
{
    return x==root[x]?x:Find(root[x]);
}

void Union(int x,int y)
{
    x=Find(x),y=Find(y);
    if(x!=y){
        root[y]=x;
        num[x]+=num[y];
        ans--;
    }
}

void del(int x)
{
    int pre=Find(id[x]);
    num[pre]--;
    if(num[pre]==0)ans--;
    cnt++;
    num[cnt]=1;
    root[cnt]=cnt;
    id[x]=cnt;
    ans++;
}

int main()
{
    int t,n,m,x,y;
    scanf("%d",&t);
    for(int T=1;T<=t;T++){
        scanf("%d%d",&n,&m);
        char s[10];
        Init(n);
        printf("Case #%d:\n",T);
        for(int i=0;i<m;i++){
            scanf("%s",s);
            getchar();
            if(s[0]=='q'){
                printf("%d\n",ans);
            }else if(s[0]=='t'){
                scanf("%d%d",&x,&y);
                del(y);
                Union(id[x],id[y]);
            }else if(s[0]=='f'){
                scanf("%d%d",&x,&y);
                int xx=Find(id[x]),yy=Find(id[y]);
                if(xx==yy)continue;
                if(num[xx]>num[yy])printf("%d is winner!\n",x),Union(id[x],id[y]);
                else if(num[xx]<num[yy])printf("%d is winner!\n",y),Union(id[y],id[x]);
                else printf("Either is winner!\n");
            }else if(s[0]=='r'){
                scanf("%d",&x);
                del(x);
            }
        }
    }
    return 0;
}