题目地址:https://pintia.cn/problem-sets/994805046380707840/problems/994805121500692480
技巧
判断一个数是不是偶数,判断它的个位数是不是偶数就行啦!
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <map>
#include <string>
#include <algorithm>
#include <math.h>
#define debug true
using namespace std;
int main() {
#if debug
freopen("in.txt", "r", stdin);
#endif // debug
double mult1 = 1;
double mult2 = 1;
string str;
int fu = 0;
cin >> str;
if (str[0] == '-')
{
fu = 1;
mult1 = 1.5;
}
// 判断一个数是不是偶数,判断它的个位数就行啦!
if ((str[str.size() - 1] - '0')% 2 == 0)
{
mult2 = 2;
}
double count = 0;
for (size_t i = 0; i < str.size(); i++)
{
if (str[i] == '2')
{
count++;
}
}
double temp = count / (str.size() - fu);
printf("%.2lf%%", temp * mult1 * mult2 * 100);
return 0;
}