GYM101933I - Intergalactic Bidding

GYM101933I - Intergalactic Bidding

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题解：不考虑首先显然是个背包，一开始直接用set模拟，然后map存方案，这样会mle。发现物品的体积有的特殊性

only one participant was allowed to make a bid at a time,
each participant was only allowed to make one bid, and
a participant making a bid had to bid at least twice the amount of the highest
bid at the time.

于是，直接对物品排序贪心取最大即可,因为对于种题目给定的s，一定有唯一的方法组成。

#include <bits/stdc++.h>
typedef long long ll;
const int N = 1e3 + 7;
using namespace std;
struct Big {
    char x[1005]; int len;string s;
    bool operator == (const Big &A) const {
        if(A.len != len) return 0;
        for(int i = 0; i < len; ++i) if(A.x[i] != x[i]) return 0;
        return 1;
    }
    bool operator < (const Big &A) const {
        if(A.len != len) return len < A.len;
        for(int i = len-1; i >= 0; --i) if(A.x[i] != x[i]) return x[i] < A.x[i];
        return 0;
    }
    Big operator + (const Big &A) const {
        Big ans = *this;
        for(int i = 0; i < A.len; ++i) {
            ans.x[i] = ans.x[i] + A.x[i];
        }
        int mx = max(A.len, len), f = 0;
        for(int i = 0; i < mx+1; ++i) {
            if(ans.x[i] >= 10) {
                ans.x[i]-=10; ++ans.x[i+1];
            }
            if(ans.x[i]) ans.len = i+1, f = 1;
        }
        if(!f) ans.len = 1;
        return ans;
    }
    Big operator - (const Big &A) const {
        Big ans = *this; int f = 0;
        for(int i = 0; i < A.len; ++i) {
            ans.x[i] = ans.x[i] - A.x[i];
        }
        int mx = max(A.len, len);
        for(int i = 0; i < mx+1; ++i) {
            if(ans.x[i] < 0) {
                ans.x[i]+=10; --ans.x[i+1];
            }
            if(ans.x[i]) ans.len = i+1, f = 1;
        }
        if(!f) ans.len = 1;
        return ans;
    }
    void read() {
        cin >> s; len = s.size();
        for(int i = 0; i < len; ++i) x[len-i-1] = s[i]-'0';
        s.clear();
    }
    void write() {
        for(int i = len-1; i >= 0; --i) printf("%d",x[i]); putchar('\n');
    }
} s, ZER;

int n;
struct node{
    string nm; Big A;
    bool operator < (const node & a) const {
        return A < a.A;
    }
} a[N];
vector<int> ans;
int main() {
    ZER.x[0] = 0; ZER.len = 1;
    scanf("%d",&n);
    s.read();
    for(int i = 1; i <= n; ++i) {
        cin >> a[i].nm; a[i].A.read();
    }
    sort(a+1,a+1+n);
    for(int i = n ; i >= 1; --i) {
        if( a[i].A < s || s == a[i].A) {
            ans.push_back(i);
            s = s - a[i].A;
        }
    }
    if(s == ZER) {
        printf("%d\n",(int)ans.size());
        for(int i = 0; i < ans.size(); ++i) {
            cout << a[ans[i]].nm << '\n';
        }
    }
    else puts("0");
    return 0;
}