1060. Are They Equal (25)

If a machine can save only 3 significant digits, the float numbers 12300 and 12358.9 are considered equal since they are both saved as 0.123*10⁵ with simple chopping. Now given the number of significant digits on a machine and two float numbers, you are supposed to tell if they are treated equal in that machine.

Input Specification:

Each input file contains one test case which gives three numbers N, A and B, where N (<100) is the number of significant digits, and A and B are the two float numbers to be compared. Each float number is non-negative, no greater than 10¹⁰⁰, and that its total digit number is less than 100.

Output Specification:

For each test case, print in a line "YES" if the two numbers are treated equal, and then the number in the standard form "0.d₁...d_N*10^k" (d₁>0 unless the number is 0); or "NO" if they are not treated equal, and then the two numbers in their standard form. All the terms must be separated by a space, with no extra space at the end of a line.

Note: Simple chopping is assumed without rounding.

Sample Input 1:

3 12300 12358.9

Sample Output 1:

YES 0.123*10^5

Sample Input 2:

3 120 128

Sample Output 2:

NO 0.120*10^3 0.128*10^3

来源： <http://www.patest.cn/contests/pat-a-practise/1060>

#include<string>
#include <iostream>

using namespace std;


int n;
int SearchDot(string s) { //Search the pos of ‘.‘
	for (int i = 0; i < s.length(); i++) {
		if (s[i] == ‘.‘)
			return i;
	}
	return -1;
}

string ChangeToSci(string s1) {
	string s1new;

	bool isZero = true;//check whether it is 0
	for (int i = 0; i < s1.length(); i++) {
		if (s1[i] != ‘0‘&&s1[i] != ‘.‘)
			isZero = false;
	}
	if (isZero) {
		s1new += "0.";
		for (int i = 0; i < n; i++)
			s1new += ‘0‘;
		s1new += "*10^0";
		return s1new;//if 0 return
	}
	bool hengji = false;
	string temp;
	for (int i = 0; i < s1.length()-1; i++) {//remove 0 in the head such as 05.02
		
		if (s1[i+1]>=‘0‘&&s1[i+1]<=‘9‘&&s1[i] == ‘0‘&&hengji == false) {
			continue;
		}
		else {
			hengji = true;
		}
		temp += s1[i];
	}
	temp += s1[s1.length() - 1];
	s1 = temp;

	int dotPos = SearchDot(s1);
	if (dotPos == -1) {//no dot in the number ,such like 12345
		s1new += "0.";
		for (int i = 0; i < n; i++) {
			if (i < s1.length())
				s1new += s1[i];
			else
				s1new += ‘0‘;
		}
		s1new += "*10^";
		int temp = s1.length();
		if (temp == 100)
			s1new += "100";
		else if (temp >= 10) {
			s1new += temp / 10 + ‘0‘;
			s1new += temp % 10 + ‘0‘;
		}
		else
			s1new += temp + ‘0‘;
	}
	else if (dotPos != 1) {//dot not at the second pos, such like 123.45 12.3
		s1new += "0.";
		bool dotFlag = false;
		for (int i = 0; i < n; i++) {
			
			if (i < s1.length()) {
				if (s1[i] == ‘.‘) {
					dotFlag = true;
					continue;
				}
				s1new += s1[i];
			}
			else
				s1new += ‘0‘;
		}
		if (dotFlag == true) {
			if (n < s1.length())
				s1new += s1[n];
			else
				s1new += ‘0‘;
		}
		s1new += "*10^";
		int temp = dotPos;
		if (temp == 100)
			s1new += "100";
		else if (temp >= 10) {
			s1new += temp / 10 + ‘0‘;
			s1new += temp % 10 + ‘0‘;
		}
		else
			s1new += temp + ‘0‘;
	}
	else {
		if (s1[0] == ‘0‘) {//0.23 0.00023 and so on
			s1new += "0.";
			int j = 2, cnt = 0, flag = 0;
			while (true)
			{
				if (s1[j] == ‘0‘ && flag == 0)
					cnt++;
				else
					break;
				j++;
			}
			for (int i = j; i < j + n; i++) {
				if (i < s1.length())
					s1new += s1[i];
				else
					s1new += ‘0‘;
			}
			if (cnt == 0) {
				s1new += "*10^0";
			}
			else {
				s1new += "*10^-";
				int temp = cnt;
				if (temp == 100)
					s1new += "100";
				else if (temp >= 10) {
					s1new += temp / 10 + ‘0‘;
					s1new += temp % 10 + ‘0‘;
				}
				else
					s1new += temp + ‘0‘;
			}
		}
		else {//2.002 1.354 and so on
			s1new += "0.";
			for (int i = 0; i <= n; i++) {
				if (i == 1)
					continue;
				if (i < s1.length())
					s1new += s1[i];
				else
					s1new += ‘0‘;
			}
			s1new += "*10^1";
		}
	}
	return s1new;

}

int main(void) {
	
	string s1, s2;
	string s1new, s2new;
	cin >> n >> s1 >> s2;

	if (n == 0) {
		cout << "YES 0";
		return 0;
	}

	string s11, s22;
	s11 = ChangeToSci(s1);
	s22 = ChangeToSci(s2);
	if (s11 == s22) {
		cout << "YES " << s11;
	}
	else {
		cout << "NO " << s11 << " " << s22;
	}

	return 0;
}

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