Sha 10555-dead fraction) (number theory)

Link: Ultraviolet A 10555-dead Fraction

A decimal number can be any number starting from..., but it must be an infinite repeating decimal number. The decimal number should be expressed in fraction form and the denominator should be as big as possible.

Solution: How can I convert an infinite loop decimal point to a component type:

• There are decimal digits 0. abcdeee, Uncyclic part length 4, cyclic section is E, and e length is I (Suppose)
• ABCD + e999... (I bit 9) 10i

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;typedef long long ll;const int maxn = 105;const ll INF = 0x3f3f3f3f3f3f3f;char s[maxn];ll gcd (ll a, ll b) {    return b ? gcd(b, a%b) : a;}int main () {    while (scanf("%s", s) == 1 && strcmp(s, "0")) {        int len = strlen(s)-5;        ll ansu, ansd = INF;        for (int i = 0; i < len; i++)            s[i] = s[i+2];        for (int i = 0; i < len; i++) {            ll d = 1, u = 0;            for (int j = 0; j < i; j++) {                d = d * 10;                u = u * 10 + s[j] - ‘0‘;            }            ll x = 0, y = 0;            for (int j = i; j < len; j++) {                x = x * 10 + s[j] - ‘0‘;                y = y * 10 + 9;            }            d = d * y;            u = u * y + x;            ll g = gcd(d, u);            u /= g;            d /= g;            if (d < ansd) {                ansd = d;                ansu = u;            }        }        printf("%lld/%lld\n", ansu, ansd);    }    return 0;}