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https://github.com/Kiritow/OJ-Problems-Source.git
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37 lines
837 B
C++
37 lines
837 B
C++
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#include <iostream>
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#include <cstdio>
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#include <algorithm>
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#include <cmath>
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#define EPS (1e-8)
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double dp[1010];
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using namespace std;
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double cal(double a,double b,double pre,double p) {
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return (p-pre)/(1+pow(p-a,b));
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}
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double get_max(int a,double b,double pre) {
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double l = a+1 ,r = 1e10;
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while(abs(l-r)>EPS) {
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double mid = (l+r)/2.0,mmid = (r+mid)/2.0;
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if(cal(a,b,pre,mmid)<cal(a,b,pre,mid)) r = mmid;
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else l = mid;
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}
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int ans = l;
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return cal(a,b,pre,ans)>cal(a,b,pre,ans+1)?cal(a,b,pre,ans):cal(a,b,pre,ans+1);
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}
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double get(double a,double b,int n) {
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dp[0] = a;
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for(int i(1);i!=n;++i)
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dp[i] = dp[i-1] + get_max(a,b,dp[i-1]);
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return dp[n-1];
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}
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int main() {
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double a,b,n;
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int t(0);
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while(cin>>n) {
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if(n==0) break;
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cin>>a>>b;
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printf("Case %d: %.2lf\n",++t,get(a,b,n));
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}
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return 0;
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}
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