leetcode 541. Reverse String II 反转字符串-蒲公英云

leetcode 541. Reverse String II 反转字符串

清疚 2022-06-03 03:40 266阅读 0赞

Given a string and an integer k, you need to reverse the first k characters for every 2k characters counting from the start of the string. If there are less than k characters left, reverse all of them. If there are less than 2k but greater than or equal to k characters, then reverse the first k characters and left the other as original.
Example:
Input: s = “abcdefg”, k = 2
Output: “bacdfeg”
Restrictions:
The string consists of lower English letters only.
Length of the given string and k will in the range [1, 10000]

本题题意十分简单，就是做一个字符串的反转，注意是没2k个子串中前k个反转，其余的不变

建议和leetcode 344. Reverse String 反转字符串一起学习

代码如下：

#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <string>
#include <climits>
#include <algorithm>
#include <sstream>
#include <functional>
#include <bitset>
#include <numeric>
#include <cmath>
using namespace std;
class Solution 
{
public:
    string reverseStr(string s, int k)
    {
        int count = s.length() / k;
        for (int i = 0; i <= count; i++)
        {
            if (i % 2 == 0)
            {
                if (i*k + k < s.length())
                    reverse(s.begin()+i*k,s.begin() + i*k+k);
                else
                    reverse(s.begin() + i*k, s.end());
            }
        }
        return s;
    }
};