Buggy python submission (verdict: Time Limit Exceeded):
import sys
sys.setrecursionlimit(10**5+10)
input = sys.stdin.readline
def I(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI2(N): return [list(map(int, sys.stdin.readline().split())) for i in range(N)]
def S(): return sys.stdin.readline()
def LS(): return sys.stdin.readline().split()
def LS2(N): return [sys.stdin.readline().split() for i in range(N)]
def FILL(i,h,w): return [[i for j in range(w)] for k in range(h)]
MOD = 1000000007
INF = float("inf")

N = I()
p = [float(x) for x in input().split()]

dp = FILL(0,N+1,N+1)
dp[0][0] = 1
dp[0][1] = 0
for i in range(N):
    for f in range(i+2):
        if f == 0:
            dp[i+1][f] = dp[i][f]*(1-p[i])
        else:
            dp[i+1][f] = dp[i][f]*(1-p[i]) + dp[i][f-1]*p[i]
ans = 0
for i in range(N+1):
    if i>N/2:
        ans += dp[N][i]
print(ans)


Fixed submission:
import sys
import math
from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN
from collections import deque
from bisect import bisect_left
from itertools import product
def I(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI2(N): return [list(map(int, sys.stdin.readline().split())) for i in range(N)]
#文字列を一文字ずつ数字に変換、'5678'を[5,6,7,8]とできる
def LSI(): return list(map(int, list(sys.stdin.readline().rstrip())))
def LSI2(N): return [list(map(int, list(sys.stdin.readline().rstrip()))) for i in range(N)]
#文字列として取得
def ST(): return sys.stdin.readline().rstrip()
def LST(): return sys.stdin.readline().rstrip().split()
def LST2(N): return [sys.stdin.readline().rstrip().split() for i in range(N)]
def FILL(i,h): return [i for j in range(h)]
def FILL2(i,h,w): return [FILL(i,w) for j in range(h)]
def FILL3(i,h,w,d): return [FILL2(i,w,d) for j in range(h)]
def FILL4(i,h,w,d,d2): return [FILL3(i,w,d,d2) for j in range(h)]
def sisha(num,digit): return Decimal(str(num)).quantize(Decimal(digit),rounding=ROUND_HALF_UP)
#'0.01'や'1E1'などで指定、整数に戻すならintをかます
MOD = 1000000007
INF = float("inf")
sys.setrecursionlimit(10**6+10)

N = I()
P = list(map(float,input().split()))
dp = FILL2(0,N+3,N+3)
dp[0][0] = 1
for i in range(N):
    for j in range(N):
        dp[i+1][j+1] += dp[i][j]*P[i]
        dp[i+1][j] += dp[i][j]*(1-P[i])
print(sum(dp[N][N//2+1:]))

Buggy python submission (verdict: Time Limit Exceeded):
import sys
sys.setrecursionlimit(10**5+10)
input = sys.stdin.readline
def I(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI2(N): return [list(map(int, sys.stdin.readline().split())) for i in range(N)]
def S(): return sys.stdin.readline()
def LS(): return sys.stdin.readline().split()
def LS2(N): return [sys.stdin.readline().split() for i in range(N)]
def FILL(i,h,w): return [[i for j in range(w)] for k in range(h)]
MOD = 1000000007
INF = float("inf")

N = I()
p = [float(x) for x in input().split()]

dp = FILL(0,N+1,N+1)
dp[0][0] = 1
dp[0][1] = 0
for i in range(N):
    for f in range(N+1):
        if f == 0:
            dp[i+1][f] = dp[i][f]*(1-p[i])
        else:
            dp[i+1][f] = dp[i][f]*(1-p[i]) + dp[i][f-1]*p[i]
ans = 0
for i in range(N+1):
    if i>N/2:
        ans += dp[N][i]
print(ans)

Fixed submission:
import sys
import math
from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN
from collections import deque
from bisect import bisect_left
from itertools import product
def I(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI2(N): return [list(map(int, sys.stdin.readline().split())) for i in range(N)]
#文字列を一文字ずつ数字に変換、'5678'を[5,6,7,8]とできる
def LSI(): return list(map(int, list(sys.stdin.readline().rstrip())))
def LSI2(N): return [list(map(int, list(sys.stdin.readline().rstrip()))) for i in range(N)]
#文字列として取得
def ST(): return sys.stdin.readline().rstrip()
def LST(): return sys.stdin.readline().rstrip().split()
def LST2(N): return [sys.stdin.readline().rstrip().split() for i in range(N)]
def FILL(i,h): return [i for j in range(h)]
def FILL2(i,h,w): return [FILL(i,w) for j in range(h)]
def FILL3(i,h,w,d): return [FILL2(i,w,d) for j in range(h)]
def FILL4(i,h,w,d,d2): return [FILL3(i,w,d,d2) for j in range(h)]
def sisha(num,digit): return Decimal(str(num)).quantize(Decimal(digit),rounding=ROUND_HALF_UP)
#'0.01'や'1E1'などで指定、整数に戻すならintをかます
MOD = 1000000007
INF = float("inf")
sys.setrecursionlimit(10**6+10)

N = I()
P = list(map(float,input().split()))
dp = FILL2(0,N+3,N+3)
dp[0][0] = 1
for i in range(N):
    for j in range(N):
        dp[i+1][j+1] += dp[i][j]*P[i]
        dp[i+1][j] += dp[i][j]*(1-P[i])
print(sum(dp[N][N//2+1:]))