藍橋杯13屆JAVA A組國賽

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package 藍橋杯國賽;
// 貪心選個數最少的進行擺
// 2:1 ,3:1, 4:1,5 : 3,6:3,7:1
// 選 1，7，4，2，3，5，9
// 然后都選滿10個
public class 火彩棒數字 {public static void main(String[] args){System.out.print("9999999999777777777755555555554444444444333333333322222222221111111111");}
}

package 藍橋杯國賽;
import java.util.Scanner;
//1:無需package
//2: 類名必須Main, 不可修改
//C28 * f[i] 錯排公式//f[i] = (i - 1) (f[i - 1] + f[i - 2])public class 小藍與鑰匙 {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 藍橋杯國賽;
import java.util.Scanner;public class 內存空間 {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 藍橋杯國賽;import java.util.Scanner;
// 由之前算出當n > 30 f[] > 1e6public class 斐波那契數組 {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 藍橋杯國賽;
import java.util.*;
// 特殊的dijkstra
// dijkstra是每個選取最小的，如果彈出的節點已徑擴展過了，就continue
// 然后擴展每個點計算經過該點的最短路徑,如果小于就原最短路徑，則入堆
// 這里特殊的邊權值是動態變化的
// tt < g 則當前路口為綠燈
// g < tt < g + d 則當前路口為黃燈且下一個燈為紅燈
// g + d < tt < g + d + r 則當前路口為紅燈
// g + d + r < tt < g + 2d + r 則當前路口為黃燈且下一個燈為綠燈 
public class 交通信號 {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 藍橋杯國賽;
import java.util.*;
//本題使用bigInteger會超時
//可以利用位運算找規律
//1
//121
//12321
//1234321
//123454321
//12345654321//一共有2n-1位，
// 當i <= n 時
// 從右往左第i行，這一行有n - i + 1個 i，上面是i - 2，i - 4，.... 2(或1）
// 這一位是[(n - i + 1) * i + k] k = i/2*(i - 2)/2 或 k = (i-1) / 2*(i - 1)/2
// 當 i > n 時
// 末尾為奇數時對1到末尾相加，為偶數時0 到 n 相加public class 六六大順 {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 藍橋杯國賽;import java.util.Scanner;//x的上一層的取值范圍y 為 12 ～ 22，且為合數
//當y 為 12 ：9 ～ 12
//當y 為 14 ：14 - 7 + 1 = 8
//當y 為 15 ：15 - 5 + 1 = 9
// ····// 第一步求x 最大素數 z(如果是質數，就-1）
// y的取之范圍為 (x - z + 1, x )，y為合數
// 然后在求區間中?最大素數 + 1 最大的數 
public class 選素數 {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);}}
}

國賽ac難度是大于省賽的，最后倆題放棄了