【题解】洛谷 P1080 国王游戏

目录

• 题目
• 思路
• $Code$

---

题目

P1080 国王游戏

思路

贪心+高精度。按$a \times b$从小到大排序就可以了、

$Code$

#include<bits/stdc++.h>
#define MAXN 1001
#define rr register
using namespace std;
const int Big_B = 10; const int Big_L = 1;
inline int intcmp_ (int a, int b) { if (a > b) return 1; return a < b ? -1 : 0; }

struct Int  {
#define rg register
    inline int max (int a, int b) { return a > b ? a : b; }
    inline int min (int a, int b) { return a < b ? a : b; }
    std :: vector <int> c; Int () {} typedef long long LL; 
    Int (int x) { for (; x > 0; c.push_back (x % Big_B), x /= Big_B); }
    Int (LL x) { for (; x > 0; c.push_back (x % Big_B), x /= Big_B); }
    inline void CrZ () { for (; !c.empty () && c.back () == 0; c.pop_back ()); }
    inline Int &operator += (const Int &rhs){
        c.resize (max (c.size (), rhs.c.size ())); rg int i, t = 0, S;
        for (i = 0, S = rhs.c.size (); i < S; ++ i)
            c[i] += rhs.c[i] + t, t = c[i] >= Big_B, c[i] -= Big_B & (-t);
        for (i = rhs.c.size (), S = c.size (); t && i < S; ++ i)
            c[i] += t, t = c[i] >= Big_B, c[i] -= Big_B & (-t);
        if (t) c.push_back (t); return *this;
    }
    inline Int &operator -= (const Int &rhs){
        c.resize (max (c.size (), rhs.c.size ())); rg int i, t = 0, S;
        for (i = 0, S = rhs.c.size (); i < S; ++ i)
            c[i] -= rhs.c[i] + t, t = c[i] < 0, c[i] += Big_B & (-t);
        for (i = rhs.c.size (), S = c.size (); t && i < S; ++ i)
            c[i] -= t, t = c[i] < 0, c[i] += Big_B & (-t);
        CrZ (); return *this;
    }
    inline Int &operator *= (const Int &rhs){
        rg int na = c.size (), i, j, S, ai; 
        c.resize (na + rhs.c.size ()); LL t;
        for (i = na - 1; i >= 0; -- i){
            ai = c[i], t = 0, c[i] = 0;
            for (j = 0, S = rhs.c.size (); j < S; ++ j){
                t += c[i + j] + (LL) ai * rhs.c[j];
                c[i + j] = t % Big_B, t /= Big_B;
            }
            for (j = rhs.c.size (), S = c.size (); t != 0 && i + j < S; ++ j)
                t += c[i + j], c[i + j] = t % Big_B, t /= Big_B;
            assert (t == 0);
        }
        CrZ (); return *this;
    }
    inline Int &operator /= (const Int &rhs) { return *this = div (rhs); }
    inline Int &operator %= (const Int &rhs) { return div (rhs), *this; }
    inline Int &shlb (int l = 1){
        if (c.empty ()) return *this; c.resize (c.size () + l);rg int i;
        for (i = c.size () - 1; i >= l; -- i) c[i] = c[i - l];
        for (i = 0; i < l; ++ i) c[i] = 0;
        return *this;
    }
    inline Int &shrb (int l = 1){
        for (rg int i = 0; i < c.size () - l; ++ i) c[i] = c[i + l];
        c.resize (max (c.size () - l, 0)); return *this;
    }
    inline Int div (const Int &rhs){
        assert (!rhs.c.empty ()); Int q, r; rg int i; if (rhs > *this) return 0;
        q.c.resize (c.size () - rhs.c.size () + 1); rg int _l, _r, mid;
        for (i = c.size () - 1; i > c.size () - rhs.c.size (); -- i) r.shlb (), r += c[i];
        for (i = c.size () - rhs.c.size (); i >= 0; -- i){
            r.shlb (); r += c[i]; 
            if (r.Comp (rhs) < 0) q.c[i] = 0;
            else {
                _l = 0, _r = Big_B;
                for (; _l != _r; ){
                    mid = _l + _r >> 1;
                    if ((rhs * mid).Comp (r) <= 0) _l = mid + 1; else _r = mid;
                }
                q.c[i] = _l - 1, r -= rhs * q.c[i];
            }
        }
        q.CrZ (), *this = r; return q;
    }
    inline int Comp (const Int &rhs) const {
        if (c.size () != rhs.c.size ()) return intcmp_ (c.size (), rhs.c.size ());
        for (rg int i = c.size () - 1; i >= 0; -- i) 
            if (c[i] != rhs.c[i]) return intcmp_ (c[i], rhs.c[i]);
        return 0;
    }
    friend inline Int operator + (const Int &lhs, const Int &rhs)
    { Int res = lhs; return res += rhs; }
    inline friend Int operator - (const Int &lhs, const Int &rhs){ 
        if (lhs < rhs){
            putchar ('-'); 
            Int res = rhs; return res -= lhs;
        }
        else { Int res = lhs; return res -= rhs; }
    }
    friend inline Int operator * (const Int &lhs, const Int &rhs)
    { Int res = lhs; return res *= rhs; }
    friend inline Int operator / (const Int &lhs, const Int &rhs)
    { Int res = lhs; return res.div (rhs); }
    friend inline Int operator % (const Int &lhs, const Int &rhs)
    { Int res = lhs; return res.div (rhs), res; }
    friend inline std :: ostream &operator << (std :: ostream &out, const Int &rhs){ 
        if (rhs.c.size () == 0) out << "0";
        else {
            out << rhs.c.back ();
            for (rg int i = rhs.c.size () - 2; i >= 0; -- i)
                out << std :: setfill ('0') << std :: setw (Big_L) << rhs.c[i];
        }
        return out;
    } 
    friend inline std :: istream &operator >> (std :: istream &in, Int &rhs){
        static char s[100000];
        in >> s + 1; int Len = strlen (s + 1);
        int v = 0; LL r = 0, p = 1;
        for (rg int i = Len; i >= 1; -- i){
            ++ v; r = r + (s[i] - '0') * p, p *= 10;
            if (v == Big_L) rhs.c.push_back (r), r = 0, v = 0, p = 1;
        }
        if (v != 0) rhs.c.push_back (r); return in;
    }
    friend inline bool operator < (const Int &lhs, const Int &rhs)
    { return lhs.Comp (rhs) < 0; }
    friend inline bool operator <= (const Int &lhs, const Int &rhs)
    { return lhs.Comp (rhs) <= 0; }
    friend inline bool operator > (const Int &lhs, const Int &rhs)
    { return lhs.Comp (rhs) > 0; }
    friend inline bool operator >= (const Int &lhs, const Int &rhs)
    { return lhs.Comp (rhs) >= 0; }
    friend inline bool operator == (const Int &lhs, const Int &rhs)
    { return lhs.Comp (rhs) == 0; }
    friend inline bool operator != (const Int &lhs, const Int &rhs)
    { return lhs.Comp (rhs) != 0; }
#undef rg
};

struct qwq {
    Int a,b,cj;
}qaq[MAXN];

bool cmp(qwq x,qwq y) {
    return x.cj<y.cj;
}

int Main (){
    int n;
    cin>>n;
    cin>>qaq[0].a>>qaq[0].b;
    for(rr int i=1;i<=n;++i) {
        cin>>qaq[i].a;
        cin>>qaq[i].b;
        qaq[i].cj=qaq[i].a*qaq[i].b;
    }
    sort(qaq+1,qaq+n+1,cmp);
    Int maxx=0,flag=1;
    for(rr int i=1;i<=n;++i) {
        flag*=qaq[i-1].a;
        maxx=max(maxx,flag/qaq[i].b);
    }
    cout<<maxx;
    return 0;
}
int ZlycerQan = Main ();
int main (int argc, char *argv[]) {;}

原文链接:https://www.cnblogs.com/poi-bolg-poi/p/11623430.html
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