A rogue solution to a disgusting question (HUD 4002 find the maximum)

A disgusting question .....

Proof can be issued ....

Euler's function: Phi (n) = N (1-1/P1) (1-1/P2) (1-1/P3 )....

N/PHI (n) = (P1/(P1-1) (P2/(P2-1 ))....

To maximize N/PHI (N), Because p/(p-1) decreases with the increase of P, P should be as small as possible, P/(p-1)> 1 so P is as much as possible...

That is to say, start from the smallest prime number and start multiplication enumeration to find the number smaller than N and closest to n ....

 

 

Yes, =, =! This Java cannot be handed in! It can be used during the competition. It cannot be used now .... Are you selling cute ?!

The vomit is complete...

I use Java to create a table that is multiplied by the first n prime numbers ....

Then open the array in C to save it... Then compare it with the input string n ..

Table hitting:

View code

import java.io.*;import java.math.*;import java.util.*;public class Main {        public static void main(String[] args) {        int t, i, j;        int N = 1000;        BigInteger n, m, tmp, one;        Scanner cin = new Scanner (System.in);                one = BigInteger.ONE;        boolean[] b= new boolean[N];        int[] pri = new int[N];                int num = 0;        for(i = 0; i < N; ++i) b[i] = true;        for(i = 2; i < N; ++i) {            for(j = i*i; j < N; j += i)                b[j] = false;        }        for(i = 2; i < N; ++i) {            if(b[i])    {pri[num++] = i; }        }        n = cin.nextBigInteger();        m = one;        for(i = 0; i < num; ++i) {            tmp = m.multiply(BigInteger.valueOf(pri[i]));            m = tmp;            System.out.println("\"" + m + "\"" + ",");            if(tmp.compareTo(n) > 0)    break;        }    }}

Comparison:

View code

#include <iostream>#include <cstdio>#include <cmath>#include <vector>#include <cstring>#include <algorithm>#include <string>#include <set>#include <ctime>#include <queue>#include <map>#include <sstream>#define CL(arr, val)    memset(arr, val, sizeof(arr))#define REP(i, n)       for((i) = 0; (i) < (n); ++(i))#define FOR(i, l, h)    for((i) = (l); (i) <= (h); ++(i))#define FORD(i, h, l)   for((i) = (h); (i) >= (l); --(i))#define L(x)    (x) << 1#define R(x)    (x) << 1 | 1#define MID(l, r)   (l + r) >> 1#define Min(x, y)   x < y ? x : y#define Max(x, y)   x < y ? y : x#define E(x)    (1 << (x))const int eps = 1e-6;const int inf = ~0u>>2;typedef long long LL;using namespace std;char st[55][300] = {    "2",    "6",    "30",    "210",    "2310",    "30030",    "510510",    "9699690",    "223092870",    "6469693230",    "200560490130",    "7420738134810",    "304250263527210",    "13082761331670030",    "614889782588491410",    "32589158477190044730",    "1922760350154212639070",    "117288381359406970983270",    "7858321551080267055879090",    "557940830126698960967415390",    "40729680599249024150621323470",    "3217644767340672907899084554130",    "267064515689275851355624017992790",    "23768741896345550770650537601358310",    "2305567963945518424753102147331756070",    "232862364358497360900063316880507363070",    "23984823528925228172706521638692258396210",    "2566376117594999414479597815340071648394470",    "279734996817854936178276161872067809674997230",    "31610054640417607788145206291543662493274686990",    "4014476939333036189094441199026045136645885247730",    "525896479052627740771371797072411912900610967452630",    "72047817630210000485677936198920432067383702541010310",    "10014646650599190067509233131649940057366334653200433090",    "1492182350939279320058875736615841068547583863326864530410",    "225319534991831177328890236228992001350685163362356544091910",    "35375166993717494840635767087951744212057570647889977422429870",    "5766152219975951659023630035336134306565384015606066319856068810",    "962947420735983927056946215901134429196419130606213075415963491270",    "166589903787325219380851695350896256250980509594874862046961683989710",    "29819592777931214269172453467810429868925511217482600306406141434158090",    "5397346292805549782720214077673687806275517530364350655459511599582614290",    "1030893141925860008499560888835674370998623848299590975192766715520279329390",    "198962376391690981640415251545285153602734402721821058212203976095413910572270",    "39195588149163123383161804554421175259738677336198748467804183290796540382737190",    "7799922041683461553249199106329813876687996789903550945093032474868511536164700810",    "1645783550795210387735581011435590727981167322669649249414629852197255934130751870910",    "367009731827331916465034565550136732339800312955331782619462457039988073311157667212930",    "83311209124804345037562846379881038241134671040860314654617977748077292641632790457335110",    "19078266889580195013601891820992757757219839668357012055907516904309700014933909014729740190",    "4445236185272185438169240794291312557432222642727183809026451438704160103479600800432029464270",    "1062411448280052319722448549835623701226301211611796930357321893850294264731624591303255041960530",    "256041159035492609053110100510385311995538591998443060216114576417920917800321526504084465112487730",    "64266330917908644872330635228106713310880186591609208114244758680898150367880703152525200743234420230",};int main() {    //freopen("data.in", "r", stdin);    int t, i;    char s[200];    scanf("%d", &t);    while(t--) {        scanf("%s", s);        int ls = strlen(s);        for(i = 0; i < 54; ++i) {            int lt = strlen(st[i]);            if(lt > ls)  break;            else if(lt < ls)    continue;            if(strcmp(st[i], s) > 0)    break;        }        printf("%s\n", st[i-1]);    }    return 0;}