package 蓝桥杯国赛;
// 贪心选个数最少的进行摆
// 2:1 ,3:1, 4:1,5 : 3,6:3,7:1
// 选 1，7，4，2，3，5，9
// 然后都选满10个
public class 火彩棒数字 {
public static void main(String[] args)
{
System.out.print("9999999999777777777755555555554444444444333333333322222222221111111111");
}
}
package 蓝桥杯国赛; import java.util.Scanner; //1:无需package //2: 类名必须Main, 不可修改 //C28 * f[i] 错排公式 //f[i] = (i - 1) (f[i - 1] + f[i - 2]) public class 小蓝与钥匙 { static int N = 100; static long[] f = new long[N]; public static void main(String[] args) { long ans = 1; f[2] = 1; for(int i = 3;i < N;i++) f[i] = (i - 1) * (f[i - 1] + f[i - 2]); for(long i = 0;i < 14;i++) ans = ans * (28 - i) / (i + 1); System.out.println(ans * f[14]); } }
package 蓝桥杯国赛; import java.util.Scanner; public class 内存空间 { public static void main(String[] args) { Scanner in=new Scanner(System.in); int t=in.nextInt(); long sum=0; in.nextLine(); while(t-->0){ String []s=in.nextLine().split(" "); if(s[0].equals("int")){ String[]s1=s[1].split(","); sum+=4*s1.length; }else if(s[0].equals("long")){ String[]s1=s[1].split(","); sum+=8*s1.length; }else if(s[0].equals("String")){ String[]s1=s[1].split(","); for(String ss:s1){ int index=ss.indexOf("\""); int tmp=ss.indexOf("\"",index+1)-index-1; sum+=tmp; } }else if(s[0].equals("int[]")) { for(int i=2;i<s.length;i++){ int l=s[i].indexOf("["); int r=s[i].indexOf("]"); int tmp=Integer.parseInt(s[i].substring(l+1,r)); sum+=4*tmp; } }else if(s[0].equals("long[]")) { for(int i=2;i<s.length;i++){ int l=s[i].indexOf("["); int r=s[i].indexOf("]"); int tmp=Integer.parseInt(s[i].substring(l+1,r)); sum+=8*tmp; } } } long gb,mb,kb,k; gb=sum/1024/1024/1024; mb=sum%(1024*1024*1024)/1024/1024; kb=sum%(1024*1024)/1024; k=sum%1024; String res=""; if (gb != 0) res += gb + "GB"; if (mb != 0) res += mb + "MB"; if (kb != 0) res += kb + "KB"; if (k != 0) res += k + "B"; System.out.println(res); } }
package 蓝桥杯国赛;
import java.util.Scanner;
// 由之前算出当n > 30 f[] > 1e6
public class 斐波那契数组 {
static int N = 100100;
static int[] f = new int[N],a = new int[N];
public static void main(String[] args)
{
f[1] = 1;f[2] = 1;
for(int i = 3;i <= 30;i++)
f[i] = f[i - 1] + f[i - 2];
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt();
for(int i = 1;i <= n;i++)
a[i] = scanner.nextInt();
int ans = 0,m = n;
if(n > 30) n = 30;
for(int i = 1;i <= n;i++) {
int cnt = 0;
if(a[i] % f[i] == 0) {
int t = a[i] / f[i];
for(int j = 1;j <= n;j++)
if(f[j] * t == a[j]) cnt++;
ans = Math.max(ans,cnt);
}
}
System.out.print(m - ans);
}
}
package 蓝桥杯国赛;
import java.util.*;
// 特殊的dijkstra
// dijkstra是每个选取最小的，如果弹出的节点已径扩展过了，就continue
// 然后扩展每个点计算经过该点的最短路径,如果小于就原最短路径，则入堆
// 这里特殊的边权值是动态变化的
// tt < g 则当前路口为绿灯
// g < tt < g + d 则当前路口为黄灯且下一个灯为红灯
// g + d < tt < g + d + r 则当前路口为红灯
// g + d + r < tt < g + 2d + r 则当前路口为黄灯且下一个灯为绿灯
public class 交通信号 {
static final int N = 1000010, M = 4 * N;
static int[] h = new int[N], e = new int[M], ne = new int[M], g = new int[M], r = new int[M], d = new int[M], f = new int[M];
static long[] times = new long[N];
static int idx = 0;
static void add(int a, int b, int green, int red, int dist, int flag) {
e[idx] = b; g[idx] = green; r[idx] = red;
d[idx] = dist; ne[idx] = h[a]; f[idx] = flag; h[a] = idx++;
}
static long dijkstra(int n, int m, int s, int t) {
Arrays.fill(times, Long.MAX_VALUE);
times[s] = 0;
PriorityQueue<Pair> pq = new PriorityQueue<>((a,b) -> Long.compare(a.dist,b.dist));
pq.offer(new Pair(s, 0));
while (!pq.isEmpty()) {
Pair pair = pq.poll();
int u = pair.node;
long dist = pair.dist;
if (dist > times[u]) continue;
for (int i = h[u]; i != -1; i = ne[i]) {
int j = e[i];
long gr = g[i], re = r[i], di = d[i], fl = f[i];
long tot = gr + re + 2 * di;
long curt = dist % tot;
if (fl == 1) curt = curt >= gr ? tot - curt : 0;
else curt = curt >= gr + di && curt < gr + di + re ? 0 : curt < gr + di ? gr + di - curt : tot - curt + gr + di;
long newDist = dist + curt + di;
if (newDist < times[j]) {
times[j] = newDist;
pq.offer(new Pair(j, newDist));
}
}
}
return times[t] > Long.MAX_VALUE / 2 ? -1 : times[t];
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt(),m = scanner.nextInt();
int s = scanner.nextInt(),t = scanner.nextInt();
Arrays.fill(h, -1);
for (int i = 0; i < m; i++) {
int a = scanner.nextInt(), b = scanner.nextInt();
int green = scanner.nextInt(),red = scanner.nextInt();
int dist = scanner.nextInt();
add(a, b, green, red, dist, 1); add(b, a, green, red, dist, 0);
}
System.out.println(dijkstra(n, m, s, t));
}
static class Pair {
private final int node;
private final long dist;
public Pair(int node, long dist) {
this.node = node;
this.dist = dist;
}
}
}
import java.util.*;
public class Main {
static final int MAXV = 10;
static final int mod = 1000000007;
static int solve(int[] B, int N) {
int[][][] f = new int[2][MAXV][MAXV];
int cur = 0, ans = 0;
for (int i0 = 0; i0 < MAXV; ++i0) {
for (int i1 = 0; i1 < MAXV; ++i1) {
cur = 0;
Arrays.stream(f[cur]).forEach(arr -> Arrays.fill(arr, 0));
f[cur][i0][i1] = 1;
for (int i = 2; i < N; i++) {
cur ^= 1;
Arrays.stream(f[cur]).forEach(arr -> Arrays.fill(arr, 0));
for (int A0 = 0, prev = cur ^ 1; A0 < MAXV; ++A0) {
for (int A1 = 0; A1 < MAXV; ++A1) {
if (f[prev][A0][A1] == 0) continue;
for (int A2 = 0; A2 < MAXV; ++A2) {
if (Math.max(Math.max(A0, A1), A2) != B[i - 1]) continue;
if (i == N - 1) {
if (Math.max(Math.max(A1, A2), i0) != B[i] || Math.max(Math.max(i0, i1), A2) != B[0]) continue;
}
f[cur][A1][A2] += f[cur ^ 1][A0][A1];
f[cur][A1][A2] %= mod;
}
}
}
}
for (int A0 = 0; A0 < MAXV; ++A0) {
for (int A1 = 0; A1 < MAXV; ++A1) {
ans += f[cur][A0][A1];
ans %= mod;
}
}
}
}
return ans;
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int N = scanner.nextInt();
int[] B = new int[N];
for (int i = 0; i < N; ++i) {
B[i] = scanner.nextInt();
}
System.out.println(solve(B, N));
}
}
package 蓝桥杯国赛;
import java.util.*;
//本题使用bigInteger会超时
//可以利用位运算找规律
//1
//121
//12321
//1234321
//123454321
//12345654321
//一共有2n-1位，
// 当i <= n 时
// 从右往左第i行，这一行有n - i + 1个 i，上面是i - 2，i - 4，.... 2(或1）
// 这一位是[(n - i + 1) * i + k] k = i/2*(i - 2)/2 或 k = (i-1) / 2*(i - 1)/2
// 当 i > n 时
// 末尾为奇数时对1到末尾相加，为偶数时0 到 n 相加
public class 六六大顺 {
public static void main(String[] args)
{
Scanner scanner = new Scanner(System.in);
long n = scanner.nextLong();
StringBuilder x = new StringBuilder();
long carry = 0, t;
for (long i = 1; i <= n; i++) {
t = (n - i + 1) * i;
if (i % 2 == 0) t += i * (i - 2) / 4;
else t += (i - 1) * (i - 1) / 4;
t = t * 36 + carry;
x.append(t % 10);
carry = t / 10;
}
for (long i = n + 1; i < 2 * n; i++) {
long last_value = 2 * n - i;
long cnt = (last_value + 1) / 2;
if (i % 2 == 0) t = (last_value + 2) * cnt / 2;
else t = (last_value + 1) * cnt / 2;
t = t * 36 + carry;
x.append(t % 10);
carry = t / 10;
}
x.append(carry);
System.out.println(x.reverse().toString());
}
}
package 蓝桥杯国赛;
import java.util.Scanner;
//x的上一层的取值范围y 为 12 ～ 22，且为合数
//当y 为 12 ：9 ～ 12
//当y 为 14 ：14 - 7 + 1 = 8
//当y 为 15 ：15 - 5 + 1 = 9
// ····
// 第一步求x 最大素数 z(如果是质数，就-1）
// y的取之范围为 (x - z + 1, x )，y为合数
// 然后在求区间中➖最大素数 + 1 最大的数
public class 选素数 {
static boolean is_prime(int n)
{
if(n <= 1) return false;
for(int i = 2;i <= n / i;i++)
if(n % i == 0) return false;
return true;
}
static int lpf(int n)
{
int ans = 2;
for(int i = 2; i <= n/i;i++)
{
while(n % i == 0)
{
ans = i;
n /= i;
}
}
return ans;
}
public static void main(String[] args)
{
Scanner scanner = new Scanner(System.in);
int x = scanner.nextInt();
if(is_prime(x)) {
System.out.println(-1);
}else {
int z = lpf(x);
int l = x - z + 1;
int ans = (int)2e6;
for(int i = l;i <= x;i++) {
if(is_prime(i)) continue;
ans = Math.min(ans,i - lpf(i) + 1);
}
System.out.println(ans);
}
}
}
国赛ac难度是大于省赛的，最后俩题放弃了
![[Kotlin]创建一个私有包并使用](https://img-blog.csdnimg.cn/direct/c2c510e486244c47a43bc8bd93c9ff65.png)
