Codeforce:b. mark the dust sweeper [fill 0 + move]

analysis

Remove useless prefixes 0
then , In the middle of the 0 One by one （ As a delivery ）
Make up one 0 Need an extra
Then fill in the middle 0 Then you can transfer effectively
So is a Sum of and then 0 If so, add one

ac code

import sys
input = sys.stdin.readline

for _ in range(int(input())):
    n = int(input())
    a = list(map(int, input().split()))
    # flatten
    # find the pattern
    # fill the 0 take 1 step
    # after fill all the 0, can move from head to tail
    ptr = 0
    while ptr < n and a[ptr] == 0:
        ptr += 1
    ans = 0
    for i in range(ptr, n - 1):
        if a[i] == 0:
            ans += 1
        else:
            ans += a[i]
    print(ans)

summary

Construction question + Follow 0 He Fei 0 Dealing with