poj 1759 Garland

#include<cstdio>#include<iostream>#define Max 1008#define eps 1e-6double a,h2;int N;double solve(int t){    return ( (t-1)*h2 - (t-2)*a + t*t - 3*t + 2);}bool judge(){    bool flag=true;    for(int i=2;i<=N;i++)        if(solve(i)<0) {     flag=false;     break; }    return flag;}int main(){    int i,j;    double left,mid,right,temp;    double ans=2000000000.0;    scanf("%d %lf",&N,&a);    for(left=a,right=0.0;left-right>eps;)    {        mid=(left+right)/2;        h2=mid;        if(judge())        { temp=solve(N); if(temp<ans)     ans=temp; left=mid;        }        else right=mid;    }    printf("%.2lfn",ans);}