題解:
從後面往前加上本金乘上概率即可,控制好多少個可以走到這裏。
#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <string>
#include <vector>
#include <bitset>
#include <stack>
#include <cmath>
#include <deque>
#include <queue>
#include <list>
#include <set>
#include <map>
#pragma comment(linker, "/STACK:1024000000,1024000000")
#define line printf("---------------------------\n")
#define mem(a, b) memset(a, b, sizeof(a))
#define pi acos(-1)
using namespace std;
typedef long long ll;
const double eps = 1e-9;
const int inf = 0x3f3f3f3f;
const int mod = 1e9+7;
const int maxn = 100+10;
double dp[maxn];
int main(){
int t, cas = 1;
scanf("%d", &t);
while(t--){
mem(dp, 0);
int n;
scanf("%d", &n);
for(int i = 0; i < n; i++){
scanf("%lf", &dp[i]);
}
int cnt = 1;
for(int i = n-2; i >= 0; i--){
cnt = cnt > 6 ? 6 : cnt;
for(int j = 1; j <= cnt; j++){
dp[i] += dp[i+j]/cnt;
}
cnt++;
}
printf("Case %d: %.6lf\n", cas++, dp[0]);
}
}