Codeforces Beta Round #6 (Div. 2 Only)

Codeforces Beta Round #6 (Div. 2 Only)

A

水题

#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))
#define maxn 1000010
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */

int Check(int a,int b,int c){
    if(a+b>c&&a+c>b&&b+c>a) return 1;
    if(a+b==c||a+c==b||b+c==a) return 0;
    return -1;
}

int main(){
    #ifndef ONLINE_JUDGE
      //  freopen("1.txt","r",stdin);
    #endif
    int a,b,c,d;
    cin>>a>>b>>c>>d;
    int flag=-1;
    flag=max(flag,Check(a,b,c));
    flag=max(flag,Check(a,c,d));
    flag=max(flag,Check(a,b,d));
    flag=max(flag,Check(b,c,d));
    if(flag==1) cout<<"TRIANGLE"<<endl;
    else if(!flag) cout<<"SEGMENT"<<endl;
    else cout<<"IMPOSSIBLE"<<endl;
}

B

水题

#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))
#define maxn 1000010
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */

int n,m;
char flag;
string str[105];
map<char,int>mp;

int dir[4][2]={0,1,1,0,0,-1,-1,0};
void Check(int x,int y){
    for(int i=0;i<4;i++){
        int xx=x+dir[i][0];
        int yy=y+dir[i][1];
        if(xx>=0&&xx<n&&yy>=0&&yy<m){
            if(str[xx][yy]!='.'&&str[xx][yy]!=flag)
                mp[str[xx][yy]]=1;
        }
    }
}

int main(){
    #ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
    #endif
    cin>>n>>m>>flag;
    for(int i=0;i<n;i++) cin>>str[i];
    for(int i=0;i<n;i++){
        for(int j=0;j<m;j++){
            if(str[i][j]==flag) Check(i,j);
        }
    }
    cout<<mp.size()<<endl;
}

C

水题

#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))
#define maxn 1000010
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */

int n;

int a[100005];

int main(){
    #ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
    #endif
    int ans1=0,ans2=0;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    if(n==1){
        cout<<"1 0"<<endl;
        return 0;
    }
    int L=1,R=n;
    while(L<=R){
        if(ans1<=ans2)
            ans1+=a[L++];
        else{
            ans2+=a[R--];
        }
    }
    L--;
    R++;
    cout<<L<<" "<<n-R+1<<endl;

}

D

因为数据量很小，所以直接暴力搜索（好像也可以用DP）

#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))
#define maxn 1000010
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */

int n,a,b;
int h[25];
vector<int>ve,V;
int ans=99999999;

void dfs(int pos,int co){
    if(co>=ans) return;
    if(pos==n){
        if(h[pos]<0){
            ans=co;
            V=ve;
        }
        return;
    }
    for(int i=0;i<=max(h[pos-1]/b+1,max(h[pos]/a+1,h[pos+1]/b+1));i++){
        if(h[pos-1]<b*i){
            h[pos-1]-=b*i;
            h[pos+1]-=b*i;
            h[pos]-=a*i;
            for(int j=0;j<i;j++) ve.push_back(pos);
            dfs(pos+1,co+i);
            for(int j=0;j<i;j++) ve.pop_back();
            h[pos-1]+=b*i;
            h[pos+1]+=b*i;
            h[pos]+=a*i;
        }
    }
}

int main(){
    #ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
    #endif
    std::ios::sync_with_stdio(false);
    cin>>n>>a>>b;
    for(int i=1;i<=n;i++) cin>>h[i];
    dfs(2,0);
    cout<<ans<<endl;
    for(int i=0;i<V.size();i++){
        cout<<V[i]<<" ";
    }
    cout<<endl;
}

E

可以用set或线段树找区间最大最小值，然后不断枚举区间

#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))
#define maxn 1000010
typedef long long ll;
/*#ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
#endif */

ll n;
multiset<ll>se;
ll a[100005];

int main(){
    #ifndef ONLINE_JUDGE
        freopen("1.txt","r",stdin);
    #endif
    ll k;
    cin>>n>>k;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    ll L=1;
    ll Max=0;
    ll tou,wei;
    for(int i=1;i<=n;i++){
        se.insert(a[i]);
        tou=*se.begin();
        wei=*se.rbegin();
        while(abs(tou-wei)>k){
            se.erase(se.find(a[L++]));
            tou=*se.begin();
            wei=*se.rbegin();
        }
        ll tmp=se.size();
        Max=max(Max,tmp);
    }
    se.clear();
    vector<pair<int,int> >ve;
    L=1;
    for(int i=1;i<=n;i++){
        se.insert(a[i]);
        tou=*se.begin();
        wei=*se.rbegin();
        while(abs(tou-wei)>k){
            se.erase(se.find(a[L++]));
            tou=*se.begin();
            wei=*se.rbegin();
        }
        if(se.size()==Max){
            ve.push_back(make_pair(L,i));
        }
    }
    cout<<Max<<" "<<ve.size()<<endl;
    for(int i=0;i<ve.size();i++){
        cout<<ve[i].first<<" "<<ve[i].second<<endl;
    }
}