題目鏈接:點擊打開鏈接
題意:
給定n個數,
構造一個序列(只能選給出的n個數,但數字可重復用)
使得序列嚴格遞增且相鄰的兩個數字不互質
思路:
因為是嚴格遞增,所以給輸入的n個數排個序,相當於選n個數中的子序列了。
把每個數都分解質因數,然後用質因數轉移方程即可。
import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; import java.math.BigInteger; import java.text.DecimalFormat; import java.util.ArrayDeque; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.Comparator; import java.util.Deque; import java.util.HashMap; import java.util.Iterator; import java.util.LinkedList; import java.util.Map; import java.util.PriorityQueue; import java.util.Scanner; import java.util.Stack; import java.util.StringTokenizer; import java.util.TreeMap; import java.util.TreeSet; import java.util.Queue; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; public class Main { int[] prime = new int[N], len = new int[N]; int primenum;//有primenum個素數 math.h void PRIME(int Max_Prime){ primenum=0; prime[primenum++]=2; for(int i=3;i<=Max_Prime;i+=2) for(int j=0;jsqrt((double)i) || j==primenum-1) { prime[primenum++]=i; break; } } int n; int[] a = new int[N]; ArrayList G = new ArrayList(); void go(int x){ G.clear(); for(int i = 0; prime[i]*prime[i]<= x; i++){ if(x%prime[i] == 0){ G.add(prime[i]); while(x%prime[i]==0)x/=prime[i]; } } if(x>1) G.add(x); } void work() throws Exception{ n = Int(); for(int i = 0; i < n; i++)a[i] = Int(); for(int i = 0; i < N; i++)len[i] = 0; Arrays.sort(a, 0, n); PRIME(100000); for(int i = 0; i < n; i++){ go(a[i]); int mx = 0; for(int j = 0; j < G.size(); j++){ mx = max(len[G.get(j)] , mx); } for(int j = 0; j < G.size(); j++) len[G.get(j)] = mx+1; } int ans = 1; for(int i = 0; i < N; i++)ans = max(ans, len[i]); out.println(ans); } public static void main(String[] args) throws Exception{ Main wo = new Main(); in = new BufferedReader(new InputStreamReader(System.in)); out = new PrintWriter(System.out); // in = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt")))); // out = new PrintWriter(new File("output.txt")); wo.work(); out.close(); } static int N = 100005; static int M = 101; DecimalFormat df=new DecimalFormat("0.0000"); static int inf = (int)1e8; static long inf64 = (long) 1e18*2; static double eps = 1e-8; static double Pi = Math.PI; static int mod = (int)1e9 + 7 ; private String Next() throws Exception{ while (str == null || !str.hasMoreElements()) str = new StringTokenizer(in.readLine()); return str.nextToken(); } private int Int() throws Exception{ return Integer.parseInt(Next()); } private long Long() throws Exception{ return Long.parseLong(Next()); } private double Double() throws Exception{ return Double.parseDouble(Next()); } StringTokenizer str; static Scanner cin = new Scanner(System.in); static BufferedReader in; static PrintWriter out; /* class Edge{ int from, to, dis, nex; Edge(){} Edge(int from, int to, int dis, int nex){ this.from = from; this.to = to; this.dis = dis; this.nex = nex; } } Edge[] edge = new Edge[M<<1]; int[] head = new int[N]; int edgenum; void init_edge(){for(int i = 0; i < N; i++)head[i] = -1; edgenum = 0;} void add(int u, int v, int dis){ edge[edgenum] = new Edge(u, v, dis, head[u]); head[u] = edgenum++; }/**/ int upper_bound(int[] A, int l, int r, int val) {// upper_bound(A+l,A+r,val)-A; int pos = r; r--; while (l <= r) { int mid = (l + r) >> 1; if (A[mid] <= val) { l = mid + 1; } else { pos = mid; r = mid - 1; } } return pos; } int Pow(int x, int y) { int ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; y >>= 1; x = x * x; } return ans; } double Pow(double x, int y) { double ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; y >>= 1; x = x * x; } return ans; } int Pow_Mod(int x, int y, int mod) { int ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; ans %= mod; y >>= 1; x = x * x; x %= mod; } return ans; } long Pow(long x, long y) { long ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; y >>= 1; x = x * x; } return ans; } long Pow_Mod(long x, long y, long mod) { long ans = 1; while (y > 0) { if ((y & 1) > 0) ans *= x; ans %= mod; y >>= 1; x = x * x; x %= mod; } return ans; } int gcd(int x, int y){ if(x>y){int tmp = x; x = y; y = tmp;} while(x>0){ y %= x; int tmp = x; x = y; y = tmp; } return y; } int max(int x, int y) { return x > y ? x : y; } int min(int x, int y) { return x < y ? x : y; } double max(double x, double y) { return x > y ? x : y; } double min(double x, double y) { return x < y ? x : y; } long max(long x, long y) { return x > y ? x : y; } long min(long x, long y) { return x < y ? x : y; } int abs(int x) { return x > 0 ? x : -x; } double abs(double x) { return x > 0 ? x : -x; } long abs(long x) { return x > 0 ? x : -x; } boolean zero(double x) { return abs(x) < eps; } double sin(double x){return Math.sin(x);} double cos(double x){return Math.cos(x);} double tan(double x){return Math.tan(x);} double sqrt(double x){return Math.sqrt(x);} }