delete pics to save space

history_source/ccf 入门篇/U4/4.2.5.cpp

@@ -0,0 +1,48 @@
+#include<iostream>
+#include<cmath>
+using namespace std;
+int k;
+long long n;
+long double f(long long n)
+{
+	long double s=0;
+	for(int i=1;i<=n;i++)
+	{
+		s=s+1.0/i;
+	}
+	return s;
+}
+int main()
+{
+	while(true)
+	{
+		cin>>k;
+		if(k>=10) n=pow(k,4);
+		else{
+		if(k>=6) n=pow(k,3);
+		else n=k*k;
+	    }
+	    if(k<12){
+		while(f(n)<=k)n+=3;
+		if(f(n-1)>k) 
+		{if(f(n-2)>k) cout<<n-2<<endl;
+		else cout<<n-1<<endl;}
+		else cout<<n<<endl;}
+		else {
+			if(k>=14) n=pow(k,5);
+			if(k>=15) while(f(n)<=k) n+=4096;
+			else while(f(n)<=k) n+=2048;
+			if(f(n-2048)>k) n-=2048;
+			if(f(n-1024)>k) n-=1024;
+			if(f(n-512)>k) n-=512;
+			if(f(n-256)>k) n-=256;
+			if(f(n-128)>k) n-=128;
+			if(f(n-64)>k) n-=64;
+			if(f(n-32)>k) n-=32;
+			if(f(n-16)>k) n-=16;
+			while(f(n)>k) n--;
+			n++;
+			cout<<n<<endl;
+		}
+	}
+}