[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 = 1010;

#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 = 0;

inline int read() {
    int x = 0; char c = gc;
    while(c < '0' || c > '9') c = gc;
    while(c >= '0' && c < '9') x = x * 10 + c - '0', c = gc;
    return x;
}

int main() {
    n = read(); ak = read(); bk = read();
    for(int i = 1; i <= n; i ++) G[i].A = read(), G[i].B = read(), G[i].AB = G[i].A * G[i].B;
    sort(G + 1, G + n + 1);
    sum = ak;
    for(int i = 1; i <= n; i ++) {
        LL imp = sum / G[i].B;
        if(!imp) imp = 1;
        Answer = max(Answer, imp);
        sum *= G[i].A;    
    }
    if(Answer == 0) Answer = 1;
    cout << Answer;
    return 0;
}
/*
3 
1 1 
2 3 
7 4 
4 6 
*/

#include <bits/stdc++.h>

using namespace std;

int now[20010],sum[20010],ans[20010],add[20010];

struct Node {
    int a;
    int b;
    long long a_b;
} node[1010];

int read() {
    int ans = 0, flag = 1;
    char ch = getchar();
    while( (ch > '9' || ch < '0') && ch != '-' ) ch = getchar();
    if(ch == '-') flag = -1, ch = getchar();
    while(ch >= '0' && ch <= '9') ans = ans * 10 + ch - '0', ch = getchar();
    return ans * flag;
}
void times(int x) {
    memset(add, 0, sizeof(add));
    for(int i = 1; i <= ans[0]; i ++) {
        ans[i] = ans[i] * x;
        add[i+1] += ans[i] / 10;
        ans[i] %= 10;
    }
    for(int i = 1; i <= ans[0] + 4; i ++) {
        ans[i] += add[i];
        if(ans[i]>=10) {
            ans[i+1]+=ans[i]/10;
            ans[i]%=10;
        }
        if(ans[i]!=0) {
            ans[0]=max(ans[0],i);
        }
    }
    return ;
}
int divition(int x) {
    memset(add,0,sizeof(add));
    int q=0;
    for(int i=ans[0]; i>=1; i--) {
        q*=10;
        q+=ans[i];
        add[i]=q/x;
        if(add[0]==0 && add[i]!=0) {
            add[0]=i;
        }
        q%=x;
    }
    return 0;
}
bool compare() {
    if(sum[0]==add[0]) {
        for(int i=add[0]; i>=1; i--) {
            if(add[i]>sum[i]) return 1;
            if(add[i]<sum[i]) return 0;
        }
    }
    if(add[0]>sum[0]) return 1;
    if(add[0]<sum[0]) return 0;
}
void cp () {
    memset(sum,0,sizeof(sum));
    for(int i=add[0]; i>=0; 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=0; i<=n; i++) {
        node[i].a=read(),node[i].b=read();
        node[i].a_b=node[i].a*node[i].b;
    }
    sort(node+1,node+n+1,cmp);
    ans[0]=1,ans[1]=1;
    for(int i=1; i<=n; i++) {
        times(node[i-1].a);
        divition(node[i].b);
        if(compare()) {
            cp();
        }
    }
    for(int i=sum[0]; i>=1; i--)
        printf("%d",sum[i]);
    return 0;
}