python 代码

# 读取输入的 n 和 m
n, m = map(int, input().split())

l = [0] * (m + 1)
r = [0] * (m + 1)
d = [0] * (n + 2)
s = [0] * (n + 1)
for i in range(1,m + 1):
    l[i],r[i] = map(int,input().split())
    d[l[i]] += 1
    d[r[i] + 1] -= 1
for i in range(1,n + 1):
    s[i] = s[i - 1] + d[i]
p0 = [0] * (n + 1)
p1 = [0] * (n + 1)
for i in range(1, n + 1):
    p0[i] = p0[i - 1]
    p1[i] = p1[i - 1]
    if s[i] == 1:
        p1[i] = p1[i] + 1
    if s[i] == 0:
        p0[i] = p0[i] + 1
for i in range(1,m + 1):
    ans = p0[n] - p0[r[i]] + p0[l[i] - 1] + p1[r[i]] - p1[l[i] - 1]
    print(ans)

# ----------------------------------裸差分----------------------------------------------#
# n,m = map(int,input().split())
# l = [0] * (m + 1)
# r = [0] * (m + 1)
# store = [0] * (n + 2)

# def insert(l,r):
#     store[l] += 1
#     store[r + 1] -= 1

# def dec(l,r):
#     tmp[l] -= 1
#     tmp[r + 1] += 1

# for i in range(1,m + 1):
#     l[i],r[i] = map(int,input().split())
#     insert(l[i],r[i])

# for i in range(1,m + 1):
#     cnt = 0
#     tmp = store[:]
#     dec(l[i],r[i])

#     for i in range(1,n + 1):
#         tmp[i] = tmp[i] + tmp[i - 1]
#         if tmp[i] == 0:
#             cnt = cnt + 1
#     print(cnt)