delete pics to save space

1.1857.cpp

@@ -0,0 +1,38 @@
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+using namespace std;
+const int maxn=20005;
+int n,a,p[maxn],cnt,v[maxn],sg[maxn],step[maxn];
+int main()
+{
+	#ifdef local
+	freopen("pro.in","r",stdin);
+	#endif
+	scanf("%d",&n);
+	for(int i=2;i<maxn;i++) v[i]=i;
+	for(int i=2;i<maxn;i++)
+	{
+		if(v[i]==i) { p[cnt++]=i; }
+		for(int j=0;j<cnt&&p[j]*i<maxn&&p[j]<=v[i];j++) v[p[j]*i]=p[j];
+	}
+	for(int i=2;i<maxn;i++)
+	{
+		for(int j=0;j<cnt&&p[j]<=i;j++) if(sg[i-p[j]]==0) sg[i]=1;
+		if(sg[i]==0) for(int j=0;j<cnt&&p[j]<=i;j++) step[i]=max(step[i-p[j]]+1,step[i]);
+		else
+		{
+			for(int j=0;j<cnt&&p[j]<=i;j++) if(sg[i-p[j]]==0)
+			{
+				if(step[i]==0) step[i]=step[i-p[j]]+1;
+				else step[i]=min(step[i],step[i-p[j]]+1);
+			}
+		}
+	}
+	for(int i=1;i<=n;i++)
+	{
+		scanf("%d",&a);
+		printf("%d\n",sg[a]?step[a]:-1);
+	}
+	return 0;
+}