LeetCode Weekly Contest 23

1. Reverse String II

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]

实现

#include <iostream>

#include <algorithm>

using namespace std;

class Solution {

public:

    string reverseStr(string s, int k) {

        int k2 = k * 2;

        int counter = 0;

        int size = s.length();

        string result = "";

        while(1) {

            if (counter + k > size) {

                string tmp(s.begin()+counter, s.end());

                reverse(tmp.begin(), tmp.end());

                result += tmp;

                return result;

            } else {

                if (counter + k2 <= size) {

                    string tmp(s.begin()+counter, s.begin()+counter+k);

                    reverse(tmp.begin(), tmp.end());

                    result += tmp;

                    string tmp2(s.begin()+counter+k, s.begin()+counter+k2);

                    result += tmp2;

                    counter += k2;

                } else {

                    string tmp(s.begin()+counter, s.begin()+counter+k);

                    reverse(tmp.begin(), tmp.end());

                    result += tmp;

                    counter += k;

                    string tmp2(s.begin()+counter, s.end());

                    result += tmp2;

                    return result;

                }

            }

        }

    }

};

int main() {

    Solution* solution = new Solution();

    cout << solution->reverseStr("abcdefg", 10) << endl;

    return 0;

}

巴特西

LeetCode Weekly Contest 23

LeetCode Weekly Contest 23

1. Reverse String II

Example

Restrictions

实现

2. Minimum Time Difference

3. Construct Binary Tree from String

4. Word Abbreviation

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