[Luogu] 国王游戏

https://www.luogu.org/problemnew/show/P1080

按照 a * b 排序

高精度

#include <bits/stdc++.h>

using namespace std;
const int N = ;

#define LL long long

int n, ak, bk;
struct Node {
    int A, B, AB;
    bool operator <(const Node a) const{return AB < a.AB;}
} G[N];

#define gc getchar()

LL sum, Answer = ;

inline int read() {
    int x = ; char c = gc;
    while(c < '' || c > '') c = gc;
    while(c >= '' && c < '') x = x *  + c - '', c = gc;
    return x;
}

int main() {
    n = read(); ak = read(); bk = read();
    for(int i = ; i <= n; i ++) G[i].A = read(), G[i].B = read(), G[i].AB = G[i].A * G[i].B;
    sort(G + , G + n + );
    sum = ak;
    for(int i = ; i <= n; i ++) {
        LL imp = sum / G[i].B;
        if(!imp) imp = ;
        Answer = max(Answer, imp);
        sum *= G[i].A;
    }
    if(Answer == ) Answer = ;
    cout << Answer;
    return ;
}
/*
3
1 1
2 3
7 4
4 6
*/

#include <bits/stdc++.h>

using namespace std;

int now[],sum[],ans[],add[];

struct Node {
    int a;
    int b;
    long long a_b;
} node[];

int read() {
    int ans = , flag = ;
    char ch = getchar();
    while( (ch > '' || ch < '') && ch != '-' ) ch = getchar();
    if(ch == '-') flag = -, ch = getchar();
    while(ch >= '' && ch <= '') ans = ans *  + ch - '', ch = getchar();
    return ans * flag;
}
void times(int x) {
    memset(add, , sizeof(add));
    for(int i = ; i <= ans[]; i ++) {
        ans[i] = ans[i] * x;
        add[i+] += ans[i] / ;
        ans[i] %= ;
    }
    for(int i = ; i <= ans[] + ; i ++) {
        ans[i] += add[i];
        if(ans[i]>=) {
            ans[i+]+=ans[i]/;
            ans[i]%=;
        }
        if(ans[i]!=) {
            ans[]=max(ans[],i);
        }
    }
    return ;
}
int divition(int x) {
    memset(add,,sizeof(add));
    int q=;
    for(int i=ans[]; i>=; i--) {
        q*=;
        q+=ans[i];
        add[i]=q/x;
        if(add[]== && add[i]!=) {
            add[]=i;
        }
        q%=x;
    }
    return ;
}
bool compare() {
    if(sum[]==add[]) {
        for(int i=add[]; i>=; i--) {
            if(add[i]>sum[i]) return ;
            if(add[i]<sum[i]) return ;
        }
    }
    if(add[]>sum[]) return ;
    if(add[]<sum[]) return ;
}
void cp () {
    memset(sum,,sizeof(sum));
    for(int i=add[]; i>=; i--) {
        sum[i]=add[i];
    }
    return ;
}
bool cmp(Node a,Node b) {
    return a.a_b<b.a_b;
}
int main() {
    int n=read();
    for(int i=; i<=n; i++) {
        node[i].a=read(),node[i].b=read();
        node[i].a_b=node[i].a*node[i].b;
    }
    sort(node+,node+n+,cmp);
    ans[]=,ans[]=;
    for(int i=; i<=n; i++) {
        times(node[i-].a);
        divition(node[i].b);
        if(compare()) {
            cp();
        }
    }
    for(int i=sum[]; i>=; i--)
        printf("%d",sum[i]);
    return ;
}