delete pics to save space

1.1463.cpp

@@ -0,0 +1,44 @@
+#include<cstdio>
+typedef long long LL;
+inline int K(int x)
+{
+	int k=0; for(;(1<<k)<=x;++k);
+	return k;
+}
+LL n,res,mxgs;
+const int p[16]={1,2,3,5,7,11,13,17,19,23,29,31,37,41,43,47};
+int limit_p[16],p1;
+void dfs(LL i,LL gs,LL num,LL mxq)
+{
+	if(num>n) return;
+	if(i>1) limit_p[i]=p1/(K(p[i])-1)+1;//ceil((p1+1)/(K(p[i])-1))
+	LL val=num*p[i],q=1,ngs=gs;
+	while(q<limit_p[i]&&q<=mxq&&val<=n)
+	{
+		ngs=gs*(q+1);
+		if(ngs>mxgs) mxgs=ngs,res=val;
+		if(ngs==mxgs&&val<res) res=val;
+		if(i==1) p1=q;
+		dfs(i+1,ngs,val,q);
+		val*=p[i],++q;
+	}
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%lld",&n);
+	if(n==1) { printf("1\n"); return 0; }
+	
+	res=mxgs=1;
+	LL x=1,t=0;
+	for(int i=1;i<16&&x<=n;++i) x*=p[i],t=i;
+	t=K(p[t])*2-1;
+	limit_p[1]=t;
+	
+	dfs(1,1,1,20);
+	
+	printf("%lld\n",res);
+	return 0;
+}