delete pics to save space

history_source/挑战程序设计竞赛/2.7.4.cpp

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+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+using namespace std;
+int m,x;
+double p;
+double dp[2][(1<<15)+1];
+void init()
+{
+	scanf("%d%lf%d",&m,&p,&x);
+}
+void solve()
+{
+	int n=1<<m;
+	double *prv=dp[0],*nxt=dp[1];
+	memset(prv,0,sizeof(double)*(n+1));
+	prv[n]=1.0;
+	for(int r=0;r<m;r++)
+	{
+		for(int i=0;i<=n;i++)
+		{
+			int jub=min(i,n-i);
+			double t=0.0;
+			for(int j=0;j<=jub;j++)
+				t=max(t,p*prv[i+j]+(1-p)*prv[i-j]);
+			nxt[i]=t;
+		}
+		swap(prv,nxt);
+	}
+	int i=(long long)x*n/1000000;
+	printf("%.6lf\n",prv[i]);
+}
+int main()
+{
+	init();
+	solve();
+	return 0;
+}