MDIGITS2 - First Number
Tác giả: happyboy99x
Ngôn ngữ: C++
#include<cstdio>
#include<cstring>
char s[500000], t[10], *p = s;
int n, k;
int main() {
scanf("%d", &n);
for(int i = 1; i <= n; p += k) sprintf(p, "%d%n", i++, &k);
sprintf(t, "%d", n);
printf("%d\n", strstr(s, t) - s + 1);
return 0;
}