557. Reverse Words in a String III

Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: "Let's take LeetCode contest"
Output: "s'teL ekat edoCteeL tsetnoc"

Note: In the string, each word is separated by single space and there will not be any extra space in the string.

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我的解答：

class Solution {
public:
    string reverseWords(string s) {
        vector<string> a = split(s, ' ');
        string s;
        for(int i = 0; i < a.size(); ++i){
            reverse(a.begin(), a.end());
            if(i != a.size() - 1){
                s += a[i];
                s += ' ';
            }else{
                s += a[i];
            }
        }
        return s;
    }
};

需要注意的是其中的std::reverse()

Reverse range

Reverses the order of the elements in the range [first,last).

The function calls iter_swap to swap the elements to their new locations.

The behavior of this function template is equivalent to:

1 2 3 4 5 6 7 8

template <class BidirectionalIterator> void reverse (BidirectionalIterator first, BidirectionalIterator last) { while ((first!=last)&&(first!=--last)) { std::iter_swap (first,last); ++first; } }

first, lastBidirectional iterators to the initial and final positions of the sequence to be reversed. The range used is[first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
BidirectionalIterator shall point to a type for which swap is properly defined.注意其中標紅的這句，包括first指向的元素但並不包括last指向的元素。