52 lines
926 B
C++
52 lines
926 B
C++
#include<iostream>
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#include<cmath>
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#include<cstdio>
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using namespace std;
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int A,B,y;
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double ans=0;
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double inline f(double x)
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{
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return A*x*x-(B*sin(x)+y);
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}
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double inline absf(double x)
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{
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if(f(x)<0)return -f(x);
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return f(x);
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}
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bool findans(double l,double r)
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{
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if(f(l)*f(r)>0)return 0;
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while(r-l>0.00000001)
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{
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double mid1=l+(r-l)/3,mid2=r-(r-l)/3;
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if(absf(mid1)<=absf(mid2))
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r=mid2;
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else
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l=mid1;
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}
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ans=l;
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return 1;
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}
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int main()
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{
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int T;
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scanf("%d",&T);
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while(T--)
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{
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scanf("%d%d%d",&A,&B,&y);
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bool marks=0;ans=0;
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for(double x=0;x<50;x=x+0.3)
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{
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if(findans(x,x+0.3))
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{
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marks=1;break;
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}
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}
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if(marks)
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printf("%.5lf\n",ans);
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else
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printf("error\n");
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}
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return 0;
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}
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