[NOIp2012提高组_Day1T2]国王游戏
1 #include<iostream>
2 #include<string.h>
3 #include<algorithm>
4 #include<stdio.h>
5 #define N 10000
6 using namespace std;
7 struct Big_Number
8 {
9 int a[N+10];
10 Big_Number()
11 {
12 memset(a,0,sizeof(a));
13 a[0]=1;
14 }
15 Big_Number(int n)
16 {
17 memset(a,0,sizeof(a));
18 a[0]=0;
19 while(n)
20 {
21 a[++a[0]]=n%10;
22 n/=10;
23 }
24 if(!a[0])
25 a[0]=1;
26 }
27 Big_Number(char *s)
28 {
29 memset(a,0,sizeof(a));
30 int len=strlen(s);
31 for(int i=1;i<=len;i++)
32 a[i]=s[len-i]-'0';
33 a[0]=len;
34 }
35 Big_Number operator*(const Big_Number &b)const
36 {
37 Big_Number c;
38 int i,j,len=a[0]+b.a[0];
39 for(i=1;i<=a[0];i++)
40 for(j=1;j<=b.a[0];j++)
41 c.a[i+j-1]+=a[i]*b.a[j];
42 for(i=1;i<len;i++){
43 c.a[i+1]+=c.a[i]/10;
44 c.a[i]%=10;
45 }
46 while(len>1&&!c.a[len])
47 len--;
48 c.a[0]=len;
49 return c;
50 }
51 Big_Number operator/(int b)const
52 {
53 Big_Number c;
54 int d=0,i,len=a[0];
55 for(i=a[0];i;i--){
56 d=d*10+a[i];
57 c.a[i]=d/b;
58 d%=b;
59 }
60 while(len>1&&!c.a[len])
61 len--;
62 c.a[0]=len;
63 return c;
64 }
65 Big_Number operator+(const Big_Number &b)const
66 {
67 Big_Number c;
68 int len=max(a[0],b.a[0]),i;
69 for(i=1;i<=len;i++){
70 c.a[i]+=a[i]+b.a[i];
71 c.a[i+1]=c.a[i]/10;
72 c.a[i]%=10;
73 }
74 len++;
75 while(len>1&&!c.a[len])
76 len--;
77 c.a[0]=len;
78 return c;
79 }
80 Big_Number operator-(const Big_Number &b)const
81 {
82 Big_Number c;
83 int i,len=a[0];
84 for(i=1;i<=len;i++)
85 {
86 c.a[i]+=a[i]-b.a[i];
87 if(c.a[i]<0)c.a[i]+=10,c.a[i+1]--;
88 }
89 while(len>1&&!c.a[len])len--;
90 c.a[0]=len;
91 return c;
92 }
93 void operator*=(const Big_Number &x){*this=*this*x;}
94 void operator/=(const int &x){*this=*this/x;}
95 void operator+=(const Big_Number &x){*this=*this+x;}
96 void operator-=(const Big_Number &x){*this=*this-x;}
97 void print(){
98 for(int i=a[0];i;i--)
99 printf("%d",a[i]);
100 }
101 bool operator>(const Big_Number&b)const
102 {
103 if(a[0]>b.a[0])
104 return 1;
105 if(a[0]<b.a[0])
106 return 0;
107 for(int i=a[0];i;i--)
108 if(a[i]>b.a[i])
109 return 1;
110 else if(a[i]<b.a[i])
111 return 0;
112 return 0;
113 }
114 bool operator<(const Big_Number&b)const
115 {
116 if(a[0]<b.a[0])
117 return 1;
118 if(a[0]>b.a[0])
119 return 0;
120 for(int i=a[0];i;i--)
121 if(a[i]<b.a[i])
122 return 1;
123 else if(a[i]>b.a[i])
124 return 0;
125 return 0;
126 }
127 bool operator<=(const Big_Number&b)const{return !(*this>b);}
128 Big_Number operator/(const Big_Number&b)const
129 {
130 Big_Number l(0),r(*this),mid;
131 while(l<r)
132 {
133 mid=(l+r+1)/2;
134 if(mid*b<=*this) l=mid;
135 else r=mid-1;
136 }
137 return l;
138 }
139 void operator/=(const Big_Number&b){*this=*this/b;}
140 };
141 struct node{int Left,Right;long long Product;};
142 inline int read()
143 {
144 int sign=1,num=0;
145 char ch=getchar();
146 while(!isdigit(ch)){if(ch=='-')sign=-1;ch=getchar();}
147 while(isdigit(ch)){num=num*10+(ch-'0');ch=getchar();}
148 return sign*num;
149 }
150 bool comp(node x,node y)
151 {
152 return x.Product<y.Product;
153 }
154 int main()
155 {
156 int n=read();
157 Big_Number ans(1);
158 node f[N+10];
159 f[0].Left=read();
160 f[0].Right=read();
161 for(int i=1;i<=n;++i)
162 {
163 f[i].Left=read();
164 f[i].Right=read();
165 f[i].Product=f[i].Left*f[i].Right;
166 }
167 sort(f+1,f+n+1,comp);
168 for(int i=1;i<=n;++i)
169 ans*=f[i-1].Left;
170 ans/=f[n].Right;
171 if(ans<1)ans=1;
172 ans.print();
173 }
