题解 | 小红的正整数构造

#include <stdio.h>
int main()
{
    int l = 0;
    int r = 0;
    int x = 0;
    scanf("%d %d %d", &l, &r, &x);
    int k = (l + x - 1) / x;
    if (x*k <= r)
    printf("%d", x*k);
    if (x*k > r)
    printf("-1");
    return 0;
}