hdu 2011 多项式求和

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <vector>
#include <cmath>
#include <queue>
#include <deque>
#include <cmath>
#include <map>

using namespace std;
typedef long long ll;

const double inf=1e20;
const int maxn=2e5+10;
const int mod=1e9+7;


int main(){
    int m;
    scanf("%d",&m);
    while(m--){
        int n;
        scanf("%d",&n);
        double num=0;
        for(int i=1;i<=n;i++){
            if(i%2){
                num+=1.0/i;
            }else{
                num-=1.0/i;
            }
        }
        printf("%.2lf\n",num);
    }
    return 0;
}