Codeforces Beta Round #3

Codeforces Beta Round #3

http://codeforces.com/contest/3

A

找规律题。但我懒得找，直接暴搜

#include<bits/stdc++.h>
using namespace std;
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define sqr(x) ((x)*(x))
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */

int book[15][15];
struct sair{
    string str[105];
    int co;
    int x,y;
};

int dir[8][2]={0,1,1,0,0,-1,-1,0,1,1,-1,-1,1,-1,-1,1};
string D[8]={"R","D","L","U","RD","LU","LD","RU"};

sair bfs(sair s){
    queue<sair>Q;
    Q.push(s);
    sair e;
    while(!Q.empty()){
        s=Q.front();
        Q.pop();
        for(int i=0;i<8;i++){
            e=s;
            e.x=s.x+dir[i][0];
            e.y=s.y+dir[i][1];
            if(e.x>=0&&e.x<8&&e.y>=0&&e.y<8&&book[e.x][e.y]!=1){
                e.str[e.co]=D[i];
                e.co++;
                Q.push(e);
                if(book[e.x][e.y]==2){
                    return e;
                }
                book[e.x][e.y]=1;
            }
        }
    }
}

int main(){
    #ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
    #endif
    string str,str1;
    cin>>str;
    sair s;
    book[7-(str[1]-'1')][str[0]-'a']=1;
    s.y=str[0]-'a',s.x=7-(str[1]-'1'),s.co=0;
    cin>>str1;
    book[7-(str1[1]-'1')][str1[0]-'a']=2;
    if(str==str1) {cout<<0<<endl;return 0;}
    s=bfs(s);
    cout<<s.co<<endl;
    for(int i=0;i<s.co;i++){
        cout<<s.str[i]<<endl;
    }
}

B

贪心题

因为体积只有1和2两种，所以每次选单位价值最大的物品。需要注意最后容量剩一个的情况，这时候需要对比是选一个好还是把容量为1的物品删去一个再添加一个容量为2的物品好

#include<bits/stdc++.h>
using namespace std;
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define sqr(x) ((x)*(x))
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */

string str;
vector<pair<ll,int> >one,two;

bool cmp(pair<ll,int>a,pair<ll,int>b){
    if(a.first==b.first) return a.second<b.second;
    return a.first>b.first;
}

int main(){
    #ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
    #endif
    ll n,m;
    cin>>n>>m;
    int v;
    ll val;
    for(int i=1;i<=n;i++){
        cin>>v>>val;
        if(v==1){
            one.push_back(make_pair(val,i));
        }
        else{
            two.push_back(make_pair(val,i));
        }
    }
    sort(one.begin(),one.end(),cmp);
    sort(two.begin(),two.end(),cmp);
    int pos1=0,pos2=0;
    ll ans=0;
    while(pos1<one.size()||pos2<two.size()){
      //  cout<<pos1<<" "<<pos2<<endl;
        if(m>=2){
            if((two[pos2].first/2)>=one[pos1].first&&pos2<two.size()){
                ans+=two[pos2].first;
                pos2++;
                m-=2;
            }
            else if(one.size()>pos1){
                ans+=one[pos1].first;
                pos1++;
                m-=1;
            }
            else{
                ans+=two[pos2].first;
                pos2++;
                m-=2;
            }
        }
        else if(m==1){
            if(pos2==two.size()){ans+=one[pos1].first;pos1++;}
            else if(pos1==one.size()){
                if(pos1==0)
                    break;
                else{
                    pos1--;
                    ans-=one[pos1].first;
                    ans+=two[pos2].first;
                    pos2++;
                }
            }
            else if(two[pos2].first>one[pos1-1].first+one[pos1].first){
                ans-=one[pos1-1].first;
                pos1--;
                ans+=two[pos2].first;
                pos2++;
            }
            else{
                ans+=one[pos1].first;
                pos1++;
            }
            m--;
        }
        else if(m==0) break;
    }
    cout<<ans<<endl;
    vector<int>pos;
    for(int i=0;i<pos1;i++) pos.push_back(one[i].second);
    for(int i=0;i<pos2;i++) pos.push_back(two[i].second);
    sort(pos.begin(),pos.end());
    for(int i=0;i<pos.size();i++){
        cout<<pos[i]<<" ";
    }
    cout<<endl;
}

C

井子棋

模拟判断各种情况就好

#include<bits/stdc++.h>
using namespace std;
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define sqr(x) ((x)*(x))
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */

string str[3];

int Check(){
    int cha=0,quan=0;
    if(str[0][0]==str[0][1]&&str[0][1]==str[0][2]&&str[0][0]=='X') cha=1;
    if(str[1][0]==str[1][1]&&str[1][1]==str[1][2]&&str[1][0]=='X') cha=1;
    if(str[2][0]==str[2][1]&&str[2][1]==str[2][2]&&str[2][0]=='X') cha=1;
    if(str[0][0]==str[1][1]&&str[1][1]==str[2][2]&&str[0][0]=='X') cha=1;
    if(str[0][0]==str[1][0]&&str[1][0]==str[2][0]&&str[0][0]=='X') cha=1;
    if(str[0][1]==str[1][1]&&str[1][1]==str[2][1]&&str[0][1]=='X') cha=1;
    if(str[0][2]==str[1][2]&&str[1][2]==str[2][2]&&str[0][2]=='X') cha=1;
    if(str[0][2]==str[1][1]&&str[1][1]==str[2][0]&&str[0][2]=='X') cha=1;

    if(str[0][0]==str[0][1]&&str[0][1]==str[0][2]&&str[0][0]=='0') quan=1;
    if(str[1][0]==str[1][1]&&str[1][1]==str[1][2]&&str[1][0]=='0') quan=1;
    if(str[2][0]==str[2][1]&&str[2][1]==str[2][2]&&str[2][0]=='0') quan=1;
    if(str[0][0]==str[1][1]&&str[1][1]==str[2][2]&&str[0][0]=='0') quan=1;
    if(str[0][0]==str[1][0]&&str[1][0]==str[2][0]&&str[0][0]=='0') quan=1;
    if(str[0][1]==str[1][1]&&str[1][1]==str[2][1]&&str[0][1]=='0') quan=1;
    if(str[0][2]==str[1][2]&&str[1][2]==str[2][2]&&str[0][2]=='0') quan=1;
    if(str[0][2]==str[1][1]&&str[1][1]==str[2][0]&&str[0][2]=='0') quan=1;
    if(quan&&cha) return -1;
    if(cha) return 1;
    if(quan) return 2;
    return 0;
}

int main(){
    #ifndef ONLINE_JUDGE
       // freopen("1.txt","r",stdin);
    #endif
    ///first second illegal the first player won the second player won  draw
    for(int i=0;i<3;i++) cin>>str[i];
    int cha=0,quan=0;
    for(int i=0;i<3;i++) for(int j=0;j<3;j++) if(str[i][j]=='X') cha++; else if(str[i][j]=='0') quan++;
    if(abs(quan-cha)>=2||quan>cha) cout<<"illegal"<<endl;
    else{
        int tmp=Check();
        if(tmp==-1) cout<<"illegal"<<endl;
        else if(tmp==1) if(cha>quan) cout<<"the first player won"<<endl;else cout<<"illegal"<<endl;
        else if(tmp==2) if(quan==cha) cout<<"the second player won"<<endl;else cout<<"illegal"<<endl;
        else{
            if(quan+cha==9){
                cout<<"draw"<<endl;
            }
            else if(cha>quan) cout<<"second"<<endl;
            else if(cha==quan) cout<<"first"<<endl;
        }
    }
}

D

括号匹配

个人感觉是道好题

先把所有的“？”变成“）”，然后当num<0时，把前面的右括号变成左括号，变的原则是b-a的最大值，最后判断是否括号匹配

#include<bits/stdc++.h>
using namespace std;
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define sqr(x) ((x)*(x))
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */
struct sair{
    ll a,b;
    int pos;
    bool operator<(const sair&bb)const{
        return (b-a)<(bb.b-bb.a);
    }
};

int main(){
    #ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
    #endif
    string str;
    cin>>str;
    ll a,b,ans=0;
    priority_queue<sair>Q;
    sair tmp;
    int num=0;
    for(int i=0;i<str.length();i++){
        if(str[i]=='('){
            num++;
        }
        else if(str[i]==')'){
            num--;
        }
        else{
            cin>>a>>b;
            tmp.a=a,tmp.b=b,tmp.pos=i;
            Q.push(tmp);
            ans+=b;
            str[i]=')';
            num--;
        }
        while(num<0){
            if(Q.size()){
                ans-=Q.top().b-Q.top().a;
                str[Q.top().pos]='(';
                Q.pop();
                num+=2;
            }
            else{
                num=-0x3f3f3f3f;
                break;
            }
        }
    }
    if(num!=0) cout<<-1<<endl;
    else{
        cout<<ans<<endl;
        cout<<str<<endl;
    }
}