摘要
Title: 3185. 构成整天的下标对数目 II
Categories: 模运算、哈希表

3185. 构成整天的下标对数目 II

题意

给你一个整数数组 hours，表示以小时为单位的时间，返回一个整数，表示满足 i < j 且 hours[i] + hours[j] 构成整天的下标对 i, j 的数目。

整天定义为时间持续时间是 24 小时的整数倍。

例如，1 天是 24 小时，2 天是 48 小时，3 天是 72 小时，以此类推。

思路

两数之和的思想，枚举右，维护左

代码

'''
Author: NEFU AB-IN
Date: 2024-07-11 16:28:48
FilePath: \LeetCode\3185\3185.py
LastEditTime: 2024-07-11 16:40:51
'''
# 3.8.19 import
import random
from collections import Counter, defaultdict, deque
from datetime import datetime, timedelta
from functools import lru_cache
from heapq import heapify, heappop, heappush, nlargest, nsmallest
from itertools import combinations, compress, permutations, starmap, tee
from math import ceil, fabs, floor, gcd, log, sqrt
from string import ascii_lowercase, ascii_uppercase
from sys import exit, setrecursionlimit, stdin
from typing import Any, Dict, List, Tuple, TypeVar, Union

# Constants
TYPE = TypeVar('TYPE')
N = int(2e5 + 10)  # If using AR, modify accordingly
M = int(20)  # If using AR, modify accordingly
INF = int(2e9)
OFFSET = int(100)

# Set recursion limit
setrecursionlimit(INF)


class Arr:
    array = staticmethod(lambda x=0, size=N: [x() if callable(x) else x for _ in range(size)])
    array2d = staticmethod(lambda x=0, rows=N, cols=M: [Arr.array(x, cols) for _ in range(rows)])
    graph = staticmethod(lambda size=N: [[] for _ in range(size)])

    @staticmethod
    def to_1_indexed(data: Union[List, str, List[List]]):
        """Adds a zero prefix to the data and returns the modified data and its length."""
        if isinstance(data, list):
            if all(isinstance(item, list) for item in data):  # Check if it's a 2D array
                new_data = [[0] * (len(data[0]) + 1)] + [[0] + row for row in data]
                return new_data, len(new_data) - 1, len(new_data[0]) - 1
            else:
                new_data = [0] + data
                return new_data, len(new_data) - 1
        elif isinstance(data, str):
            new_data = '0' + data
            return new_data, len(new_data) - 1
        else:
            raise TypeError("Input must be a list, a 2D list, or a string")


class Str:
    letter_to_num = staticmethod(lambda x: ord(x.upper()) - 65)  # A -> 0
    num_to_letter = staticmethod(lambda x: ascii_uppercase[x])  # 0 -> A
    removeprefix = staticmethod(lambda s, prefix: s[len(prefix):] if s.startswith(prefix) else s)
    removesuffix = staticmethod(lambda s, suffix: s[:-len(suffix)] if s.endswith(suffix) else s)


class Math:
    max = staticmethod(lambda a, b: a if a > b else b)
    min = staticmethod(lambda a, b: a if a < b else b)


class IO:
    input = staticmethod(lambda: stdin.readline().rstrip("\r\n"))
    read = staticmethod(lambda: map(int, IO.input().split()))
    read_list = staticmethod(lambda: list(IO.read()))


class Std:
    pass

# ————————————————————— Division line ——————————————————————


class Solution:
    def countCompleteDayPairs(self, hours: List[int]) -> int:
        # 求出任意不相同的两数相加为24的整数倍的个数
        # 全部取余，0的可以提出来，其他的加和为24,
        hours = [hour % 24 for hour in hours]

        cnt_0 = hours.count(0)
        res = (cnt_0 - 1) * cnt_0 // 2

        cnt_ = Counter()
        for hour in hours:
            if not hour:
                continue
            if cnt_.get(24 - hour):
                res += cnt_[24 - hour]
            cnt_[hour] += 1
        return res


print(Solution().countCompleteDayPairs([12, 12, 30, 24, 24]))