第十四届蓝桥杯三月真题刷题训练——第 5 天(3.8)

[Think_bird]

数的分解

#include<bits/stdc++.h>

using namespace std;

bool pd(int x)
{
    while(x)
    {
      if(x % 10 == 2 || x % 10 == 4)
        return false;
      x /= 10;
    }
    return true;
}

int main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int ans = 0;
    for(int i = 1; i < 673; i ++)
        for(int j = i + 1; j < 2019 - i - j; j ++ )
            if(pd(i) && pd(j) && pd(2019 - i - j)) ans ++;
    cout << ans;

    return 0;
}

猜生日

#include<bits/stdc++.h>

using namespace std;

int main()
{
  for(int i = 19000101; i < 20120312; i ++ )
    if(i % 2012 == 0 and i % 3 == 0 and i % 12 == 0 and i / 100 % 100 ==6 and i % 100 < 32)
    {
      cout << i;
      break;
    }

  return 0;
}

成绩统计

#include<bits/stdc++.h>

using namespace std;

int main()
{
  int n, x, T, ans1 = 0, ans2 = 0;
  cin >> n;
  T = n;
  while(T -- )
  {
    cin >> x;
    if(x >= 85) ans1 ++;
    if(x >= 60) ans2 ++;
  }
  cout << ((ans2 * 100 + n / 2) / n) << "%\n" << ((ans1 * 100 + n / 2)/ n) << "%";

  return 0;
}

最大和

#include<bits/stdc++.h>

using namespace std;

int prime(int n)
{
    bool flag = true;
    for (int i = 2; i < n; i ++ )
    {
      if (n % i == 0)
      {
        int j;
        for (j = 2; j < i; j ++ ) if (i % j == 0) break;
        if (j != i)
        {
            flag = 0;
            continue;
        }
        return i;
      }
    }
    return flag == 1 ? n : 0;
}

int main()
{
  int n;
  cin >> n;
  int a[n + 1];
  for(int i = 1; i <= n; i ++ )
  cin >> a[i];
  vector<int> dp(n + 1, INT_MIN);
  dp[1] = a[1];
  for (int i = 1; i < n; i++)
  {
    int d = prime(n - i);
    for (int j = 1; j <= d; j ++ )
    {           
      if (i + j > n) break;
      dp[i + j] = max(dp[i + j], dp[i] + a[j + i]);
    }
  }
    cout << dp[n] << endl;

  return 0;
}