查找集合中最近的元素

问题描述

假设我有一套，例如:

my_set = {"aaron", "cathy", "john", "stewie", "xavier"};

假设我想要一个这样的函数:

Say I want a function like such:

FindFirst(my_set, "a")      // returns an iterator pointing to "aaron"
FindFirst(my_set, "aaron")  // returns an iterator pointing to "aaron"
FindFirst(my_set, "bill")   // returns an iterator pointing to "cathy"
FindFirst(my_set, "zzzzz")  // returns past-the-end iterator

基本上，它接受一个值并将迭代器返回到该元素或它之后的第一个元素(如果提供的值位于集合的末尾之后，则选择过去的迭代器).

Basically, it takes a value and returns an iterator either to that element, or the first element after it (picking the past-the-end iterator if the value provided would lie after the end of the set).

标准库中是否存在这样的函数，或者我必须自己编写一个?

Does any function like this exist in the standard library, or am I going to have to write one myself?

推荐答案

​​set::lower_bound 就是你要找的函数.

set::lower_bound is the function you are looking for.

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