10029. Corona2020

Ziya suspects that he has contracted coronavirus. In connection with this, he is conducting research on his DNA, and as a result of the calculations, he finds out that three different numbers a, b and c are related to his DNA. Ziya believes that if by substituting + or - instead of the signs (<>) into the expression a <> b <> c, he can obtain the number 2020, then he has not contracted the coronavirus. Otherwise, if it is impossible to do so, then he has contracted it. Help Ziya determine if he has contracted the coronavirus.

Input. Three integers a, b, and c (1 ≤ a, b, c ≤ 10⁸) are given.

Output. If Ziya has not contracted the virus, print the expression a <> b <> c, which results in 2020. Otherwise, print the word CORONA. When outputting the expression, there should be no spaces between the numbers and operators.

Sample input 1	Sample output 1
2019 2020 2021	2019-2020+2021
Sample input 2	Sample output 2
2019 2020 2022	CORONA

SOLUTION

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Algorithm analysis

Iterate over all possible signs between the numbers a, b, and c. If the value of the resulting expression is equal to 2020, then print the expression. Otherwise, print the word CORONA.

Algorithm realization

Read the input data.

scanf("%d %d %d", &a, &b, &c);

Iterate over all possible signs between the numbers. Depending on the result, print the answer.

if (a + b + c == 2020) printf("%d+%d+%d", a, b, c); else

if (a + b - c == 2020) printf("%d+%d-%d", a, b, c); else

if (a - b + c == 2020) printf("%d-%d+%d", a, b, c); else

if (a - b - c == 2020) printf("%d-%d-%d", a, b, c); else

printf("CORONA\n");

Python realization

Read the input data.

a, b, c = map(int, input().split())

Iterate over all possible signs between the numbers. Depending on the result, print the answer.

if a + b + c == 2020:

print(f"{a}+{b}+{c}")

elif a + b - c == 2020:

print(f"{a}+{b}-{c}")

elif a - b + c == 2020:

print(f"{a}-{b}+{c}")

elif a - b - c == 2020:

print(f"{a}-{b}-{c}")

else:

print("CORONA")