YT15-HDU-How many fibs(大数相加法)
发布时间:2020-12-14 02:45:21 所属栏目:大数据 来源:网络整理
导读:Problem Description ? Recall the definition of the Fibonacci numbers: ? f1 := 1 ? f2 := 2 ? fn := fn-1 + fn-2 (n = 3) ? Given two numbers a and b,calculate how many Fibonacci numbers are in the range [a,b]. ? ? Input ? The input contains s
Problem Description?
Recall the definition of the Fibonacci numbers:
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f1 := 1 ? f2 := 2 ? fn := fn-1 + fn-2 (n >= 3) ? Given two numbers a and b,calculate how many Fibonacci numbers are in the range [a,b]. ? ? Input?
The input contains several test cases. Each test case consists of two non-negative integer numbers a and b. Input is terminated by a = b = 0. Otherwise,a <= b <= 10^100. The numbers a and b are given with no superfluous leading zeros.
? Output?
For each test case output on a single line the number of Fibonacci numbers fi with a <= fi <= b.
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? Sample Input? 10 100 1234567890 9876543210 0 0 ? Sample Output? 5 4 ? 代码如下: #include <iostream> #include <cstring> #include <cstdio> using namespace std; string add(string x,string y) //大数相加法 { int i,temp,m=0; string Fib; int lenx=x.length(); int leny=y.length(); //返回字符串x,y的长度 if (lenx<leny) //如果x比y短 { for (i=1; i<=leny-lenx; i++) //在x前面补0至与y相同的长度 x="0"+x; } else //反之 { for (i=1; i<=lenx-leny; i++) //在y前面补0至与x相同的长度 y="0"+y; } lenx = x.length(); //x长度发生变化,需要重新返回长度 for (i=lenx-1; i>=0; i--) { temp=x[i]-'0'+y[i]-'0'+m; //相同位置的数字相加并加上后一位进的数 m=temp/10; //前一位将要加上m temp%=10; //取余 Fib=char (temp+'0')+Fib; //将这一位的数放进新的字符串 } if (m!=0) Fib=char (m+'0')+Fib; //如果最高位的数大于10继续往前进 return Fib; //返回字符串 } int main() { string fibs[1005],a,b; int i; fibs[1]="1"; fibs[2]="2"; for (i=3; i<1005; i++) { fibs[i]=add(fibs[i-2],fibs[i-1]); //将前1005个斐波那契数用数组统计。 } while(cin >> a >> b) { if(a=="0" && b == "0") break; int head,end,len_a,len_b,len; len_a = a.length(); //返回区间最小值的长度 len_b = b.length(); //返回区间最大值的长度 //找到区间内最小的斐波那契数的位置 for(i = 1; i<1005; i++) { len = fibs[i].length(); //返回某一斐波那契数的长度 if(len<len_a) continue; else if(len == len_a && fibs[i]>=a) //长度相等时比较字符串的大小 { head = i; break; } else if(len > len_a) { head = i; break; } } //找到区间内最大的斐波那契数的位置 for(i = 1004; i>=1; i--) { len = fibs[i].length(); if(len>len_b) continue; else if(len == len_b && fibs[i]<=b) { end = i; break; } else if(len < len_b) { end = i; break; } } cout<<end-head+1<<endl; //首尾相减+1 } return 0; }
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