文章目录
- [1. 【2.24】P10424 [蓝桥杯 2024 省 B] 好数](#1. 【2.24】P10424 [蓝桥杯 2024 省 B] 好数)
- [2. 【2.25】P8665 [蓝桥杯 2018 省 A] 航班时间](#2. 【2.25】P8665 [蓝桥杯 2018 省 A] 航班时间)
- [3. 【2.26】P10905 [蓝桥杯 2024 省 C] 回文字符串](#3. 【2.26】P10905 [蓝桥杯 2024 省 C] 回文字符串)
- [4. 【2.27】P10425 [蓝桥杯 2024 省 B] R 格式](#4. 【2.27】P10425 [蓝桥杯 2024 省 B] R 格式)
- [5. 【2.28】P10426 [蓝桥杯 2024 省 B] 宝石组合](#5. 【2.28】P10426 [蓝桥杯 2024 省 B] 宝石组合)
- [6. 【3.1】P10912 [蓝桥杯 2024 国 B] 数星星](#6. 【3.1】P10912 [蓝桥杯 2024 国 B] 数星星)
- [7. 【3.2】P10914 [蓝桥杯 2024 国 B] 跳石头](#7. 【3.2】P10914 [蓝桥杯 2024 国 B] 跳石头)
正文
1. 【2.24】P10424 [蓝桥杯 2024 省 B] 好数
【AC_Code】
cpp
#include <iostream>
#define IOS ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
int N, cnt;
bool check(int n)
{
int number = 1;
while (n > 0)
{
if (number % 2 == 1) { if ((n % 10) % 2 == 0) return false; }
else if ((n % 10) % 2 != 0) return false;
n /= 10; number ++;
}
return true;
}
int main()
{
IOS; cin >> N;
for (int i = 1; i <= N; i ++) if (check(i)) cnt ++;
cout << cnt << '\n';
return 0;
}2. 【2.25】P8665 [蓝桥杯 2018 省 A] 航班时间
【AC_Code】
cpp
#include <iostream>
#include <iomanip>
#define IOS ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
int solve()
{
int h1, m1, s1, h2, m2, s2, d = 0; char c1, c2, c3, c4, c5, c6;
cin >> h1 >> c1 >> m1 >> c2 >> s1 >> h2 >> c3 >> m2 >> c4 >> s2;
if (cin.peek() == ' ') cin >> c5 >> d >> c6;
return (86400 * d + 3600 * h2 + 60 * m2 + s2) - (3600 * h1 + 60 * m1 + s1);
}
int main()
{
IOS; int T; cin >> T;
while (T --)
{
int ans = (solve() + solve()) >> 1;
cout << setw(2) << setfill('0') << ans / 3600 << ':'
<< setw(2) << setfill('0') << (ans % 3600) / 60 << ':'
<< setw(2) << setfill('0') << ans % 60 << '\n';
}
return 0;
}3. 【2.26】P10905 [蓝桥杯 2024 省 C] 回文字符串
【AC_Code】
cpp
#include <iostream>
#include <string>
#define IOS ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
void solve()
{
string s; cin >> s; int l = 0, r = s.length() - 1;
while (s[l] == 'l' || s[l] == 'q' || s[l] == 'b') l ++;
while (s[r] == 'l' || s[r] == 'q' || s[r] == 'b') r --;
bool flag = true;
for (int i = l, j = 0; i <= (l + r) / 2; i ++, j ++) if (s[i] != s[r - j]) flag = false;
if ( ! flag ) cout << "No\n";
else if (l == 0) cout << "Yes\n";
else if (r == s.length() - 1) cout << "No\n";
else if (s.length() - r < l) cout << "No\n";
else
{
l --; r ++;
while (s[l] == s[r] && l >= 0 && r <= s.length()) l --, r ++;
if (r == s.length() || l == -1) cout << "Yes\n";
else cout << "No\n";
}
}
int main()
{
IOS; int T; cin >> T; while (T--) solve();
return 0;
}4. 【2.27】P10425 [蓝桥杯 2024 省 B] R 格式
【AC_Code】
cpp
#include <iostream>
#include <algorithm>
#define IOS ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
const int N = 1e6;
int n, a[N], pos, len; string q;
void solve()
{
reverse(q.begin(), q.end());
pos = q.find('.'); q.erase(pos, 1); len = q.size();
for (int i = 0; i < len; i ++) a[i + 1] = q[i] - '0';
for (int i = 1; i <= n; i ++)
{
for (int i = 1; i <= len; i ++) a[i] *= 2;
for (int i = 1; i <= len; i ++) a[i + 1] += a[i] / 10, a[i] %= 10;
if (a[len + 1]) len ++;
}
if (a[pos] >= 5) a[pos + 1] ++;
for (int i = pos + 1; i <= len; i ++) a[i + 1] += a[i] / 10, a[i] %= 10;
if (a[len + 1]) len ++;
for (int i = len; i > pos; i --) cout << a[i]; cout << '\n';
}
int main()
{
IOS; cin >> n >> q; solve();
return 0;
}5. 【2.28】P10426 [蓝桥杯 2024 省 B] 宝石组合
【AC_Code】
cpp
#include <iostream>
#include <vector>
#include <algorithm>
#define IOS ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
const int MAXN = 1e5 + 10; int n, h[MAXN]; vector<int> fac[MAXN];
int gcd(int a, int b) { return __gcd(a, b); }
void solve()
{
cin >> n; for (int i = 1; i <= n; ++ i) cin >> h[i];
sort(h + 1, h + 1 + n);
for (int i = 1; i <= n; ++ i) for (int j = 1; j * j <= h[i]; ++j)
{
if (h[i] % j == 0)
{
fac[j].push_back(h[i]);
if (h[i] / j != j) fac[h[i] / j].push_back(h[i]);
}
}
for (int i = MAXN; i >= 1; -- i)
{
if (fac[i].size() >= 3)
{
int a = fac[i][0], b = fac[i][1], c = fac[i][2];
if (gcd(gcd(a, b), c) == i) { cout << a << " " << b << " " << c << "\n"; return; }
}
}
}
int main()
{
IOS; solve();
return 0;
}6. 【3.1】P10912 [蓝桥杯 2024 国 B] 数星星
【AC_Code】
cpp
#include <iostream>
#include <vector>
#include <algorithm>
#define IOS ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
const int N = 1e5 + 10, mod = 1e9 + 7;
int n, a[N], b[N], c[N], f[N], l, r, ans;
vector<int> vec[N];
int fun(int x, int y) { return 1ll * b[x] * f[y] % mod * f[x - y] % mod; }
void DFS(int x, int y)
{
for (auto n : vec[x]) if (n != y) DFS(n, x);
if (static_cast<int> (vec[x].size()) + 1 >= 1)
{
int p = min(r - 1, static_cast<int> (vec[x].size()));
for (int i = l - 1; i <= p; i ++) ans = (ans + fun(vec[x].size(), i)) % mod;
}
}
void solve()
{
cin >> n; b[0] = c[0] = 1; b[1] = 1; c[1] = 1; f[0] = 1; f[1] = 1;
for (int i = 2; i <= n; i ++)
{
b[i] = 1ll * b[i - 1] * i % mod;
c[i] = 1ll * c[mod % i] * (mod - mod / i) % mod;
f[i] = 1ll * f[i - 1] * c[i] % mod;
}
for (int i = 1; i < n; i ++)
{
int x, y; cin >> x >> y;
vec[x].push_back(y); vec[y].push_back(x);
}
cin >> l >> r;
DFS(1, 0);
cout << ans << '\n';
}
int main()
{
IOS; solve();
return 0;
}7. 【3.2】P10914 [蓝桥杯 2024 国 B] 跳石头
【AC_Code】
cpp
#include <iostream>
#include <bitset>
#define IOS ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
const int N = 4e4 + 10; int c[N], n, ans;
bitset<N> f[N];
void solve()
{
cin >> n;
for (int i = 1; i <= n; i ++)
{
cin >> c[i]; f[i][c[i]] = 1;
}
for (int i = n; i >= 1; i --)
{
if (i + c[i] <= n) f[i] |= f[i + c[i]];
if (2 * i <= n) f[i] |= f[2 * i];
ans = max(ans, (int)f[i].count());
}
cout << ans << '\n';
}
int main()
{
IOS; solve();
return 0;
}结语
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