HDU 5879 Cure(打表预处理)

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#include<cmath>using namespace std;const int maxn=300000+100;double f[maxn];char cmd[1500];int main(){    for(int i=1;i<=110291;i++)        f[i]=f[i-1]+1.0/pow(i,2);    while(scanf("%s",cmd)!=EOF)    {        int ok=0;        int n=0;        for(int i=0;cmd[i];i++){            if(cmd[i]-'0'!=0) ok=1;            if(ok) n=n*10+cmd[i]-'0';            if(n>110291) break;        }        if(n>110291) printf("1.64493\n");        else printf("%.5f\n",f[n]);    }    return 0;}