delete pics to save space

2.12558.cpp

@@ -0,0 +1,72 @@
+#include<cstdio>
+#include<cstring>
+#include<set>
+using namespace std;
+typedef long long ll;
+const int maxn=100000+10;
+set<ll> st;
+int maxed;
+bool ok;
+ll v[maxn],res[maxn];
+ll gcd(ll a,ll b){return b==0?a:gcd(b,a%b);}
+inline ll get_first(ll a,ll b){return b/a+1;}
+bool better(int d)
+{
+	for(int i=d;i>=0;i--)
+		if(res[i]!=v[i])
+			return res[i]==-1||v[i]<res[i];
+	return false;
+}
+void dfs(int pos,ll from,ll a,ll b)
+{
+	if(pos==maxed)
+	{
+		if(b%a||st.count(b/a)) return;
+		v[pos]=b;
+		if(better(pos)) memcpy(res,v,(pos+1)<<3);
+		ok=true;
+		return;
+	}
+	from=max(from,get_first(a,b));
+	for(int i=from;;i++)
+	{
+		if(a*i>=b*(maxed-pos+1)) return;
+		if(st.count(i)) continue;
+		v[pos]=i;
+		ll t1=a*i-b,t2=b*i;
+		ll g=gcd(t1,t2);
+		dfs(pos+1,i+1,t1/g,t2/g);
+	}
+	return;
+}
+ll a,b,x;
+int n,T,kase;
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&T);
+	while(T--)
+	{
+		st.clear();
+		scanf("%lld %lld %d",&a,&b,&n);
+		for(int i=0;i<n;i++)
+		{
+			scanf("%lld",&x);
+			st.insert(x);
+		}
+		ok=false;
+		for(maxed=1;;maxed++)
+		{
+			memset(res,-1,sizeof(res));
+			dfs(0,get_first(a,b),a,b);
+			if(ok) break;
+		}
+		printf("Case %d: %lld/%lld=",++kase,a,b);
+		printf("1/%lld",res[0]);
+		for(int i=1;i<=maxed;i++) printf("+1/%lld",res[i]);
+		puts("");
+	}
+	return 0;
+}