2019牛客多校第一场J题——Fraction Comparision
题目传送门
大致题意：
依次输入x,a,y,b，比较x/a和y/b的大小，前者大则输出“>”，后者大则输出“<”，相等则输出“=”。
0<=x,y<=10^18
1<=a,b<=10^9
解法一（正解）：
不能x/a和y/b直接去除比较，会爆double；
也不能直接交叉相乘后去比较，会爆long long；
故而可以化成如下的带分数形式：
解法二：C/C++高精度大数乘法
#include
memset(a,0,sizeof(a));
memset(b,0,sizeof(b));
a[0]=str3.length();
for(i=1; i<=a[0]; i++)
a[i]=str3[a[0]-i]-'0';
b[0]=str4.length();
for(i=1; i<=b[0]; i++)
b[i]=str4[b[0]-i]-'0';
memset(d,0,sizeof(d));
for(i=1; i<=a[0]; i++) //做按位乘法同时处理进位，注意循环内语句的写法。
for(j=1; j<=b[0]; j++)
{
d[i+j-1]+=a[i]*b[j];
d[i+j]+=d[i+j-1]/10;
d[i+j-1]%=10;
}
len2=a[0]+b[0]+1; //去掉最高位的0，然后输出
while((d[len2]==0)&&(len2>1))
len2--; //为什么此处要len>1??
/*for(i=len2;i>=1;i--)
cout<
if(len1>len2)
printf(">\n");
else if(len1<len2)
printf("<\n");
else
{
for(int i=len1; i>=1; i--)
{
if(c[i]>d[i])
{
printf(">\n");
break;
}
else if(c[i]<d[i])
{
printf("<\n");
break;
}
if(c[i]==d[i]&&i==1){
printf("=\n");
break;
}
}
}
}
return 0;
解法三：Java大数
import java.io.*;
import java.util.*;
import java.math.*;
public class Main {
void MAIN() {
Scanner cin=new Scanner(System.in);
while(cin.hasNext()) {
BigInteger x=cin.nextBigInteger();
BigInteger a=cin.nextBigInteger();
BigInteger y=cin.nextBigInteger();
BigInteger b=cin.nextBigInteger();
BigInteger L=x.multiply(b);
BigInteger R=y.multiply(a);
if(L.compareTo(R)<0) System.out.println("<");
else if(L.compareTo(R)>0) System.out.println(">");
else System.out.println("=");
}
}
public static void main(String[] args) {
new Main().MAIN();
}
}
import java.util.Scanner;
import java.math.BigInteger;
public class Main {
public static void main(String args[]) {
Scanner cin = new Scanner(System.in);
while(cin.hasNext()) {
BigInteger a, b, c, d;
a = cin.nextBigInteger();
b = cin.nextBigInteger();
c = cin.nextBigInteger();
d = cin.nextBigInteger();
a = a.multiply(d);
b = b.multiply(c);
if(a.compareTo(b) > 0) {
System.out.println(">");
}
else if(a.compareTo(b) == 0) {
System.out.println("=");
}
else{
System.out.println("<");
}
}
cin.close();
}
}
import java.util.Scanner;
import java.math.BigInteger;
public class Main{
public static void main(String []args){
Scanner sc = new Scanner(System.in);
while(sc.hasNext()){
String x=sc.next();
String a=sc.next();
String y=sc.next();
String b=sc.next();
BigInteger xx=new BigInteger(x);
BigInteger aa=new BigInteger(a);
BigInteger yy=new BigInteger(y);
BigInteger bb=new BigInteger(b);
BigInteger ans1=bb.multiply(xx);
BigInteger ans2=aa.multiply(yy);
if(ans1.compareTo(ans2)==-1)
System.out.println('<');
else if(ans1.compareTo(ans2)==0)
System.out.println('=');
else
System.out.println('>');
}
}
}
解法三：python3
try:
while True:
s=input()
s=s.split(' ')
if(int(s[0])*int(s[3])<int(s[1])*int(s[2])):
print("<")
elif(int(s[0])*int(s[3])==int(s[1])*int(s[2])):
print("=")
else:
print(">")
except EOFError:
pass
while 1:
try:
x,a,y,b=input().split()
x = int(x)
y = int(y)
a = int(a)
b = int(b)
if x*b==y*a:
print("=")
elif x*b<y*a:
print("<")
else:
print(">")
except:
break
while True:
try:
s = input()
x, a, y, b = map(int, s.split(" "))
ans1 = x * b
ans2 = y * a
if ans1 < ans2:
print("<")
elif ans1 == ans2:
print("=")
else:
print(">")
except EOFError:
break
解法四：__int128
#include