the reference answer GPT ᴼ ᴾ ᴱ ᴺ ᴬ ᴵ < br / > this is a simple math problem. According to the question, Bessie can only eat one haystack for dinner on the first day, so she must not receive a haystack before dinner on the first day. Next, for each haystack's arrival time, we need to determine whether the haystack arrived before dinner on the first day. If it was less than or equal to the time before dinner on the first day, then Bessie could eat the haystack at dinner on that day, or she could not.
Specifically, we can order the haystack arrival time from smallest to largest. Then iterate through the arrival time of each haystack in turn, adding one to the number of haystacks that can be eaten at dinner on the first day if the haystack's arrival time is less than or equal to that before dinner on the first day. Otherwise, nothing is done. Finally output the number of eaten haystack can be.
Here is the Python code implementation:
n, m = map(int, input().split())
hay = [0] * (m + 1)
for i in range(n):
a, b = map(int, input().split())
hay[a] += 1
hay[b + 1] -= 1
ans = 0
for i in range(1, m + 1):
hay[i] += hay[i - 1]
if hay[i] == 0:
ans += 1
print(ans)
The code first reads the data entered, including the total number of deliveries and dinner times. Each delivery package is then read through the loop and added to the appropriate location. During this process, an array "hay" of length(dinner time +1) is used to keep track of the number of hay bales at each location.
Next, loop through the array again, adding it to the value at the previous position to calculate the number of hay bales at each position. Finally, count the number of days without haystack and output it.
