judge3-2.c

#include <stdio.h>
//判定是不是一串1
int isOnes(int n) {
    while(n > 0) {
        if(n % 10 != 1)
            return 0;
        n /= 10;
    }
    return 1;
}
int ones(int n) {
    int count = 0, times = 1; //count for 計算位數, times for 乘數
    int tmp = n;
    //若不是Ones就繼續乘下去
    while(isOnes(tmp) != 1) {
        tmp = n * times;
        times++;
    }
    //計算位數
    while(tmp > 0) {
        count++;
        tmp /= 10;
    }
    return count;
}
int main() {
    int n, i, t;
    scanf("%d", &n);
    printf("%d\n", ones(n));
    return 0;
}