数组

2023-02-27 14:44:36

数组洗牌

shuffleArray.ts

          function shuffleArray
<T
>(array
: T
[]) {
  for (let i
 = array
.length
 - 1; i
 > 0; i
--) {
    const j
 = Math
.floor
(Math
.random
() * (i
 + 1));
    [array
[i
], array
[j
]] = [array
[j
], array
[i
]];
  }
  return array
;
}

数组去重

uniqueBy.ts

          function uniqueBy
<T
, K
 extends keyof T
>(array
: T
[], getKey
?: K
 | ((item
: T
) => T
[K
])) {
  const result
: T
[] = []
  const keys
 = new Set
()

  array
.forEach
(item
 => {
    const key
 = getKey
 ? (typeof getKey
 === 'function' ? getKey
(item
) : item
[getKey
]) : item
    if (!keys
.has
(key
)) {
      keys
.add
(key
)
      result
.push
(item
)
    }
  })

  return result
}

合并区间

输入：一组区间（[start, end]），例如 [[1, 3], [2, 6], [8, 10], [15, 18]]
输出：合并重叠区间后的结果，例如 [[1, 6], [8, 10], [15, 18]]

mergeIntervals.ts

          function mergeIntervals
(intervals
: Array
<[number, number]>): Array
<[number, number]> {
  if (!intervals
.length
) return []

  // 首先将区间按起始位置排序
  intervals
.sort
((a
, b
) => a
[0] - b
[0])

  const merged
 = [intervals
[0]!] // 初始化合并后的区间列表

  for (let i
 = 1; i
 < intervals
.length
; i
++) {
    const current
 = intervals
[i
]!
    const lastMerged
 = merged
.at
(-1)!

    // 如果当前区间与最后一个合并的区间重叠，则合并它们
    if (current
[0] <= lastMerged
[1]) {
      lastMerged
[1] = Math
.max
(lastMerged
[1], current
[1]) // 更新合并区间的结束位置
    } else {
      merged
.push
(current
) // 如果不重叠，直接添加当前区间
    }
  }

  return merged
}

数组洗牌数组去重合并区间