集训队第一次作业题

作业

A Design Tutorial: Learn from Math

本来打算合数筛选判断的，后来猜了下居然A啦qwq

#include<iostream>
using namespace std;
int main()
{
    int n, x, y;
    cin >> n;
    if (n % 2 == 0) cout << "4 " << n - 4 << endl;
    else cout << "9 " << n - 9 << endl;
    return 0;
}

B Design Tutorial: Learn from Life

贪心，排序后从高处开始，每次拉k人，遇到需要停下的人就把他们放下，然后继续运输

#include<iostream>
#include<algorithm>
using namespace std;
int a[2005];
int main()
{
    int n, k, ans = 0;
    cin >> n >> k;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    sort(a+1,a + n+1);
    for (int i = n; i > 0; i -= k)
        ans += 2 * a[i] - 2;
    cout << ans << endl;
    return 0;
}

C Design Tutorial: Make It Nondeterministic

给出一个人的两个名字，选择其中一个，让所有人名序列满足字典序，
第一个输入数据取最短，然后与第二个数据最短比较，不符与第二个数据最长比较，还不符就GG，符合继续比较第三个。

#include<bits/stdc++.h>
using namespace std;
struct {
    string f;
    string l;
}str[100005];
int num[100005];
bool flag = true;
int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; ++i) cin >> str[i].f>>str[i].l;
    for (int i = 1; i <= n; ++i) cin >> num[i];
    string now = min(str[num[1]].f, str[num[1]].l);
    for (int i = 2; i <= n; ++i)
    {
        string temp = min(str[num[i]].f, str[num[i]].l);
        if (now >= temp)
        {
            temp = max(str[num[i]].f, str[num[i]].l);
            if (now >= temp)
            {
                flag = false;
                break;
            }
            now = temp;
        }
        else now = temp;
    }
    if (flag)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}

F MUH and Important Things

n个任务，每个任务有难度值，在保证难度值优先最小的情况下，得到序列是否有3.排序然后遇到相当难度值考虑多情况交换

#include<iostream>
#include<algorithm>
#include<cstdio>
using namespace std;
struct arr{
    int number;
    int value;
}data1[2005];
bool cmp(const arr &a, const arr &b)
{
    return a.value < b.value;
}
int main()
{
    int n, num = 0;
    cin >> n;
    for (int i = 1; i <= n; ++i)
    {
        cin >> data1[i].value;
        data1[i].number = i;
    }
    sort(data1 + 1, data1 + n + 1, cmp); 
    for (int i = 1; i <= n - 1; ++i)
        if (data1[i].value == data1[i + 1].value) num++;
    if (num<2) {
        cout << "NO" << endl;
        return 0;
    }
    else
    {
        cout << "YES" << endl;
        for (int t = 0; t < 3; t++)                                                                                                                                                                                
       {
              for (int i = 1; i <= n; i++)
                      printf("%d ", data1[i].number);
              printf("\n");
              for (int i = 1; i < n; i++)
             {
                   if (data1[i].value == data1[i + 1].value && data1[i].number < data1[i + 1].number)
                   {
                        swap(data1[i], data1[i + 1]);
                        break;
                   }
             }
       }
    }
    return 0;
}

I - George and Accommodation

qwq

#include<iostream>    
#include<cstdio>  
using namespace std;  
int n,m;  
int main()  
{  
    scanf("%d",&n);  
    int x,y;  
    for(int i=1;i<=n;i++)  
    {  
        scanf("%d%d",&x,&y);  
        if(y-x>=2)
             m++;  
    }  
    printf("%d",m);  
    return 0;  
}