[Greed] [洛谷] P1080 国王游戏

都TM 8102年了

还在写大数

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const int MAXN = 1e5 + 10;

string prefix[MAXN];

int aa[10010] = {0}, bb[10010] = {0}, ans[2 * 10010] = {0};

string multi(string a, string b)
{
    memset(aa, 0, sizeof(aa));
    memset(bb, 0, sizeof(bb));
    memset(ans, 0, sizeof(ans));
    
    if(b.length() > a.length())
    {
        string tmp = a;
        a = b;
        b = tmp;
    }
    int lena = a.length(), lenb = b.length();
    for(int i = lena - 1, flag = 0; i >= 0 ; i--, flag++)
    {
        aa[flag] = a[i] - '0';
    }
    for(int i = lenb - 1, flag = 0; i >= 0 ; i--, flag++)
    {
        bb[flag] = b[i] - '0';
    }
    for(int i = 0; i < lenb ; i++ )
    {
        for(int j = 0 ; j < lena; j++)
        {
            ans[i + j] += aa[j] * bb[i];
        }
    }
    int flag = 2 * 10010 ;
    for(int i = 0 ; i < flag; i++) //进位
    {
        ans[i + 1] += ans[i] / 10;
        ans[i] = ans[i] % 10;
    }
    flag = 2 * 10010 ;
    for(; ans[flag] == 0;flag --);
    string sans;
    for(;flag >= 0;flag --)
        sans = sans + char(ans[flag] + '0');
    return sans;
}

string Except(string s,int x)
{
	ll cmp = 0, ok = 0;
	
	string ans = "";
	
	for(int i = 0; i < s.length(); i++)
	{
		cmp = (cmp * 10 + s[i] - '0');
		
		if(cmp >= x)
		{
			ok = 1;
			ans += (cmp / x + '0');
			cmp %= x;
		}
		else if(ok == 1)
			ans += '0';
	}
	
	return ans.empty() ? "0" : ans; 
}


struct hand
{
    int left, right;
    
}arr[MAXN];

bool cmp(hand a, hand b)
{
    return a.left * a.right < b.left * b.right; 
}

string rans;

string trans(ll x)
{
    string ret = "";

    while(x)
    {
        ret = char(x % 10 + '0') + ret;
        x /= 10;
    }

    return ret;
}
string judge(string a, string b)
{	
	if(a.length() == b.length())
	{
		if(a > b)
			return a;
		else
			return b;
	}
	if(a.length() > b.length())
	{
		return a;
	}
	return b;
}
int main()
{
    int n;

    cin>>n;

    for(int i = 0; i <= n; i++)
    {
        cin>>arr[i].left>>arr[i].right;
    }

    sort(arr + 1, arr + n + 1, cmp);
    
    prefix[0] = trans(arr[0].left);
    
    for(int i = 1; i <= n; i++)
    {
        prefix[i] = multi(trans(arr[i].left), prefix[i - 1]);
    }
        
    for(int i = 1; i <= n; i++)
    {
        rans = judge(rans, Except(prefix[i - 1],arr[i].right) );
    }

    cout<<rans<<endl;

    return 0;
}