AC代码，放心使用

#include <iostream>
using namespace std;
int main()
{
    int x, i = 1;
    float s = 0;
    cin >> x;
    while (s <= x)
    {
        s = s + 1.0 / i;
        i += 1;
    }
    cout << i - 1;
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int n, x = 1;
    float a = 0;
    cin >> n;
    while (a <= n)
    {
        a = a + 1.0 / x;
        x += 1;
    }
    cout << x - 1;
    return 0;
}

#include <iostream> 
#include <iomanip>
 using namespace std; 
int main(){ 	
    int i=0,x; 	
    cin>>x; 
    double sum=0; 	
    while(sum<=x){ 		
        i++; 		
        sum=sum+1.0/i; 	
    } 	
    cout<<i; 	
    return 0; 
}

#include <bits/stdc++.h>
using namespace std;
int x;
int n=1;
double sum;
int main(){
	cin>>x;
	while (true){
		sum+=(double)1/n;
		if (sum>x){
			cout<<n;
			return 0; 
		}
		n++;
	}
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
double x,m,sum;
int main()
{
    cin>>x;
    m=1;
    while(sum<=x)
    {
        sum+=1/m;
        m++;
    }
    cout<<m-1;
    return 0;
}

AC代码：

#include <bits/stdc++.h>
using namespace std;
int x;
double i=1,n;
int main()
{
    cin>>x;
    while(n<=x)
    {
        n+=1/i;
        i++;
    }
    cout<<i-1;//别忘了最后要减1
    return 0;
}

#include <iostream> using namespace std; int main() { int n; cin >> n; double s = 0; int i; for (i = 1;; i++) { s += 1.0 / i; if (s > n) { break; } } cout << i; return 0; }