CodeForces - 808A Lucky Year

Posted 2022-04-16 海岛Blog

A. Lucky Year
time limit per test1 second
memory limit per test256 megabytes

Apart from having lots of holidays throughout the year, residents of Berland also have whole lucky years. Year is considered lucky if it has no more than 1 non-zero digit in its number. So years 100, 40000, 5 are lucky and 12, 3001 and 12345 are not.

You are given current year in Berland. Your task is to find how long will residents of Berland wait till the next lucky year.

Input
The first line contains integer number n (1 ≤ n ≤ 10⁹) — current year in Berland.

Output
Output amount of years from the current year to the next lucky one.

Examples
input
4
output
1
input
201
output
99
input
4000
output
1000
Note
In the first example next lucky year is 5. In the second one — 300. In the third — 5000.

问题链接：CodeForces - 808A Lucky Year
问题简述：给定一个数，求比它大只有1位非0数字的数与原数的差是多少？
问题分析：（略）
AC的C++语言程序如下：

/* CodeForces - 808A Lucky Year */

#include <stdio.h>

int main()

    int n, cnt = 0;

    scanf("%d", &n);

    int t = n;
    while (t) t /= 10, cnt++;
    int ans = 1;
    for (int i = 1; i < cnt; i++)
        ans *= 10;

    printf("%d\\n", ans - n % ans);

    return 0;