//#include<bits/stdc++.h> #include<cstdlib> #include<algorithm> #include<bitset> #define PII pair<int,int> #define f first #define s second #define VI vector<LL> #define LL long long #define MP make_pair #define LD long double #define PB push_back #define ALL(V) V.begin(),V.end() #define abs(x) max((x),-(x)) #define PDD pair<LD,LD> #define VPII vector< PII > #define siz(V) ((int)V.size()) #define FOR(x, b, e) for(int x=b;x<=(e);x++) #define FORD(x, b, e) for(int x=b;x>=(e);x--) #define REP(x, n) for(int x=0;x<(int)(n);x++) #define mini(a,b) a=min(a,b) #define maxi(a,b) a=max(a,b) using namespace std; VI V; LL n; float nF = n; vector<LL> all; int cnt = 0; inline void back1(LL x, int i) { if(x > n)return; if(i >= (int)V.size())return; if(all.back() != x)all.PB(x); if((float)x * V[i] > nF)return; back1(x, i+1); back1(x * V[i], i); } void go1(VI VV, LL nn) { V = VV; n = nn; nF = n + 1e5; all = {1}; back1(1, 0); sort(ALL(all)); } void check(LL); LL prevv; LL res = 1; inline void back2(LL x, int i) { if(x > n)return; if(i >= (int)V.size())return; // fprintf(stderr, "%lld %lld %lld\n", res, n, x); if(n - (n%x) < res)return; if(prevv != x) { check(x); prevv = x; } if((float)x * V[i] > nF)return; back2(x, i+1); back2(x * V[i], i); } void go2(VI VV, LL nn) { V = VV; n = nn; nF = n + 1e5; back2(1, 0); } LL en; const int MXF = 5e4; // mała różnica 1e5-1e6 unsigned short int prep[MXF]; void do_prep() { for(auto i : all) { if(i < MXF) prep[i] = i; } FOR(i, 1, MXF-1) { maxi(prep[i], prep[i-1]); } } inline void check(LL x) { if(x > en)return; LL y = en/x; if(y < MXF) { maxi(res, x * prep[y]); return; } int idx = upper_bound(all.begin(), all.end(), y) - all.begin() - 1; maxi(res, all[idx] * x); } void calculate(VI p, LL n) { en = n; sort(ALL(p)); VI v[2]; REP(i, p.size()) v[(1-(i&1)) || i==1 || i==7].PB(p[i]); go1(v[0], n + 1); do_prep(); go2(v[1], n + 1); /* REP(u, 2) { for(auto i : v[u])cerr<<i<<" "; cerr<<endl; }*/ fprintf(stderr, "allsize: %d\n", all.size()); /* cerr<<"all.size(): "<<all.size()<<endl; cerr<<"c1, c2 "<<c1<<" "<<c2<<endl; */ printf("%lld\n", res); } void max_test(); VI primes(int); int main() { all.reserve(540000); // max_test();return 0; int k; LL n; scanf("%d%lld", &k, &n); VI p; REP(i, k) { int a; scanf("%d", &a); p.PB(a); } calculate(p, n); } // ************************************************** void max_test() { LL n = 1e18; VI p = primes(100); calculate(p, n); } bool prime(int x) { FOR(i, 2, x-1) { if(x % i == 0)return 0; } return 1; } VI primes(int x) { VI V; FOR(i, 2, x) if(prime(i)) V.PB(i); return V; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 | //#include<bits/stdc++.h> #include<cstdlib> #include<algorithm> #include<bitset> #define PII pair<int,int> #define f first #define s second #define VI vector<LL> #define LL long long #define MP make_pair #define LD long double #define PB push_back #define ALL(V) V.begin(),V.end() #define abs(x) max((x),-(x)) #define PDD pair<LD,LD> #define VPII vector< PII > #define siz(V) ((int)V.size()) #define FOR(x, b, e) for(int x=b;x<=(e);x++) #define FORD(x, b, e) for(int x=b;x>=(e);x--) #define REP(x, n) for(int x=0;x<(int)(n);x++) #define mini(a,b) a=min(a,b) #define maxi(a,b) a=max(a,b) using namespace std; VI V; LL n; float nF = n; vector<LL> all; int cnt = 0; inline void back1(LL x, int i) { if(x > n)return; if(i >= (int)V.size())return; if(all.back() != x)all.PB(x); if((float)x * V[i] > nF)return; back1(x, i+1); back1(x * V[i], i); } void go1(VI VV, LL nn) { V = VV; n = nn; nF = n + 1e5; all = {1}; back1(1, 0); sort(ALL(all)); } void check(LL); LL prevv; LL res = 1; inline void back2(LL x, int i) { if(x > n)return; if(i >= (int)V.size())return; // fprintf(stderr, "%lld %lld %lld\n", res, n, x); if(n - (n%x) < res)return; if(prevv != x) { check(x); prevv = x; } if((float)x * V[i] > nF)return; back2(x, i+1); back2(x * V[i], i); } void go2(VI VV, LL nn) { V = VV; n = nn; nF = n + 1e5; back2(1, 0); } LL en; const int MXF = 5e4; // mała różnica 1e5-1e6 unsigned short int prep[MXF]; void do_prep() { for(auto i : all) { if(i < MXF) prep[i] = i; } FOR(i, 1, MXF-1) { maxi(prep[i], prep[i-1]); } } inline void check(LL x) { if(x > en)return; LL y = en/x; if(y < MXF) { maxi(res, x * prep[y]); return; } int idx = upper_bound(all.begin(), all.end(), y) - all.begin() - 1; maxi(res, all[idx] * x); } void calculate(VI p, LL n) { en = n; sort(ALL(p)); VI v[2]; REP(i, p.size()) v[(1-(i&1)) || i==1 || i==7].PB(p[i]); go1(v[0], n + 1); do_prep(); go2(v[1], n + 1); /* REP(u, 2) { for(auto i : v[u])cerr<<i<<" "; cerr<<endl; }*/ fprintf(stderr, "allsize: %d\n", all.size()); /* cerr<<"all.size(): "<<all.size()<<endl; cerr<<"c1, c2 "<<c1<<" "<<c2<<endl; */ printf("%lld\n", res); } void max_test(); VI primes(int); int main() { all.reserve(540000); // max_test();return 0; int k; LL n; scanf("%d%lld", &k, &n); VI p; REP(i, k) { int a; scanf("%d", &a); p.PB(a); } calculate(p, n); } // ************************************************** void max_test() { LL n = 1e18; VI p = primes(100); calculate(p, n); } bool prime(int x) { FOR(i, 2, x-1) { if(x % i == 0)return 0; } return 1; } VI primes(int x) { VI V; FOR(i, 2, x) if(prime(i)) V.PB(i); return V; } |