question/search-last-index-with-binary-search-possible-duplicate-array

[giscus[bot]]

question/search-last-index-with-binary-search-possible-duplicate-array

北美前端面试攻略

https://us-fe.github.io/question/search-last-index-with-binary-search-possible-duplicate-array.html

[xiaoyu2er]

/**
 * @param {number[]} arr - ascending array with duplicates
 * @param {number} target
 * @return {number}
 */
function lastIndex(arr, target) {
  // your code here
  let left = 0, right = arr.length - 1;
  while (left < right) {
    const mid = (left + right + 1) >> 1;
    if (arr[mid] <= target) {
      left = mid;
    } else {
      right = mid - 1;
    }
  }
  return arr[left] == target ? left : -1;
}

console.log(lastIndex([1, 2, 2, 2, 3], 2) == 3);