python 代码

n,x,y,z = map(int,input().split())
tp = [] # 存储原始信息
alls = [] # 用于离散化操作
for i in range(n):
    left,right = map(int,input().split())
    tp.append((left,right))
    alls.extend([left,right])

alls = sorted(set(alls))
lens = len(alls)
cnt = [0] * (lens + 1)
def find(x):
    l,r = 0,lens - 1
    while l < r:
        mid = (l + r) // 2
        if alls[mid] < x:
            l = mid + 1
        else:
            r = mid
    return r

def insert(l,r,c):
    cnt[l] = cnt[l] + c
    cnt[r + 1] = cnt[r + 1] - c

for l,r in tp:
    l_idx = find(l)
    r_idx = find(r)
    insert(0,l_idx - 1,x)
    insert(l_idx,r_idx,y)
    insert(r_idx + 1,lens - 1,z)

res = 0
s = [0] * (lens + 1)
s[0] = cnt[0]
for i in range(1,lens):
    s[i] = s[i - 1] + cnt[i]
    if s[i] > res:
        res = s[i]
print(res)

# # 读取输入的 n, x, y, z
# n, x, y, z = map(int, input().split())

# # 存储每个奶牛的最适温度区间
# tp = []
# # 存储所有端点
# alls = []

# # 读取每个奶牛的最适温度区间并记录端点
# for _ in range(n):
#     l, r = map(int, input().split())
#     tp.append((l, r))
#     alls.extend([l, r])

# # 对端点进行排序并去重
# alls = sorted(set(alls))
# k = len(alls)

# # 初始化差分数组
# cnt = [0] * (k + 1)

# # 二分查找函数，用于找到映射前的 alls 下标
# def find(x):
#     l, r = 0, k - 1
#     while l < r:
#         mid = (l + r) // 2
#         if alls[mid] >= x:
#             r = mid
#         else:
#             l = mid + 1
#     return l

# # 差分插入操作函数
# def insert(l, r, c):
#     cnt[l] += c
#     cnt[r + 1] -= c

# # 对每个奶牛的最适温度区间进行差分插入操作
# for l, r in tp:
#     left_index = find(l)
#     right_index = find(r)
#     insert(0, left_index - 1, x)
#     insert(left_index, right_index, y)
#     insert(right_index + 1, k - 1, z)

# # 计算前缀和并找出最大值
# res = float('-inf')
# for i in range(1, k):
#     cnt[i] += cnt[i - 1]
#     res = max(res, cnt[i])

# # 输出结果
# print(res)