牛客周赛63部分题解

比赛地址：牛客竞赛_ACM/NOI/CSP/CCPC/ICPC算法编程高难度练习赛_牛客竞赛OJ (nowcoder.com)

A.小红的好数

#include<bits/stdc++.h>
using namespace std;
#define ll long long  
#define ull unsigned long long

void solve() {
    ll n;
    cin>>n;
    if(n>=10&&n<=99)
    {
        if(n%10==n/10)
        {
            cout<<"Yes";
            return;
        }
    }
    cout<<"No";
} 

signed main() {
    ios::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);

    ll t = 1; 
    // std::cin >> t;
    while (t--) {
        solve();
    }
}

B.小红的好数组

#include<bits/stdc++.h>
using namespace std;
#define ll long long  
#define ull unsigned long long

void solve() {
    ll n,m;
    cin>>n>>m;
    int num[n+10];
    for(int i=1;i<=n;i++)
    {
        cin>>num[i];
    }
    int i,j;
    int good_num=0;
    int error1;
    if(m%2)
    {
        i=(m/2)+1;
        j=m/2;
        for(;i<=n-j;i++)
        {
            error1=0;
            for(int a1=1;a1<=j;a1++)
            {
                if(num[i-a1]!=num[i+a1])
                {
                    error1++;
                }
            }
            if(error1==1)
            {
                good_num++;
            }
        }
    }
    else
    {
        i=m/2;
        j=m/2;
        for(;i<=n-j;i++)
        {
            error1=0;
            for(int a1=1;a1<=j;a1++)
            {
                if(num[i-a1+1]!=num[i+a1])
                {
                    error1++;
                }
            }
            if(error1==1)
            {
                good_num++;
            }
        }
    }
    cout<<good_num;
} 

signed main() {
    ios::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);

    ll t = 1; 
    // std::cin >> t;
    while (t--) {
        solve();
    }
}

C.小红的矩阵行走

#include<bits/stdc++.h>
using namespace std;
#define ll long long  
#define ull unsigned long long
int ssr[1001][1001];
ll n,m;
int key;
void dfs(int i,int j,int num)
{
    if(i>n||i<=0||j>m||j<=0)
    {
        return;
    }
    if(i==n&&j==m&&key==1)
    {
        key=0;
        cout<<"Yes"<<endl;
    }
    if(ssr[i+1][j]==num)
    {
        dfs(i+1,j,num);
    }
    if(ssr[i][j+1]==num)
    {
        dfs(i,j+1,num);
    }
}
void solve() {
    cin>>n>>m;
    key=1;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            cin>>ssr[i][j];
        }
    }
    dfs(1,1,ssr[n][m]);
    if(key)
    {
        cout<<"No"<<endl;
    }
} 

signed main() {
    ios::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);
    ll t = 1; 
    cin >> t;
    while (t--) {
        solve();
    }
}

D.小红的行列式构造

#include<bits/stdc++.h>
using namespace std;
#define ll long long  
#define ull unsigned long long

void solve(ll x) {
    ll a,b,c;
    if (x > 0) {
        a = x + 5; 
        b = 1;
        c = 2;
        cout << a << " -1 -1\n"
        << "-1 " << b << " -1\n"
        << "-1 -1 " << c;
    } else if (x < 0) {
        a = x-5;
        b = -1;
        c = -2;
        cout << a << " 1 1\n"
        << "1 " << b << " 1\n"
        << "1 1 " << c;
    } else { 
        cout <<"1 1 1\n"
         <<"1 1 1\n"
         <<"1 1 1\n";
    }
    
}

signed main() {
    ios::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);

    ll x;
    cin >> x;
    
    solve(x);
    
    return 0;
}