第十四届蓝桥杯 社区打卡 Day2

[TralSun]

T1

#include <iostream>
using namespace std;
bool check(int x) {
  while (x) {
    int t = x % 10;
    if (t % 2 == 0) return false;
    x /= 10;
  }
  return true;
}
int main()
{
  int t = 1;
  while (true) {
    if (check(2019 * t)) {
      cout << 2019 * t;
      break;
    }
    ++t;
  }
  return 0;
}

T2

#include <bits/stdc++.h>
using namespace std;
int fun(int x) {
  unordered_map<int, int> cnt;
  for (int i = 2; i <= sqrt(x); ++i) {
    while (x % i == 0) {
      cnt[i]++;
      x /= i;
    }
  }
  if (x > 1) cnt[x]++;
  int ans = 1;
  for (auto u : cnt) {
    ans = ans * (u.second + 1);
  }
  return ans;
}
int main()
{
  int t = 1;
  while (fun(t) != 100) {
    ++t;
  }
  cout << t;
  return 0;
}

T3

#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 100;
int a[N], n;
int main()
{
  cin >> n;
  for (int i = 1; i <= n; ++i) cin >> a[i], a[i] += a[i - 1];
  long long ans = 0;
  for (int i = 1; i <= n - 1; ++i) {
    ans += (long long)(a[i] - a[i - 1]) * (a[n] - a[i]);
  }
  cout << ans;
  return 0;
}

T4 

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
struct node {
  int val, sum;
  bool operator< (const node &a) {
    return sum < a.sum || sum == a.sum && val < a.val;
  }
};
vector<node> v;
int fun(int x) {
  int ans = 0;
  while (x) {
    ans += x % 10;
    x /= 10;
  }
  return ans;
}
int main()
{
  int n, m; cin >> n >> m;
  for (int i = 1; i <= n; ++i) {
    v.push_back({i, fun(i)});
  }
  sort(v.begin(), v.end());
  cout << v[m - 1].val;
  return 0;
}