[leetcode+剑指 offer] 左旋转字符串

2020 年 3 月 9 日 23:50:43数据结构和算法评论409字数 114阅读 0 分 22 秒阅读模式

leetcode 上开了《剑指 offer 》专栏，深夜回家特来水一下。题解后续补上~

代码：

class Solution {
private:
    void reverse(string &s, unsigned int left, unsigned int right) {
        unsigned int i;
        char x;

        for (i = left; i <= (left + right) / 2; i++) {
            x = s[i];
            s[i] = s[right - i + left];
            s[right - i + left] = x;
        }
    }

public:
    string reverseLeftWords(string s, int n) {
        reverse(s, 0, n - 1);
        reverse(s, n, s.size() - 1);
        reverse(s, 0, s.size() - 1);
        return s;
    }
};

class Solution {

private:

void reverse(string &s, unsigned int left, unsigned int right) {

unsigned int i;

char x;

for (i = left; i <= (left + right) / 2; i++) {

x = s[i];

s[i] = s[right - i + left];

s[right - i + left] = x;

}

public:

string reverseLeftWords(string s, int n) {

reverse(s, 0, n - 1);

reverse(s, n, s.size() - 1);

reverse(s, 0, s.size() - 1);

return s;

}

};

单元测试案例：

#include <gtest/gtest.h>

TEST(Solution, leetcode_1) {
    Solution s;
    string str = "abcdefg"; //"cdefgab";
    EXPECT_EQ(s.reverseLeftWords(str, 2), "cdefgab");
}

TEST(Solution, leetcode_2) {
    Solution s;
    string str = "lrloseumgh"; //"umghlrlose";
    EXPECT_EQ(s.reverseLeftWords(str, 6), "umghlrlose");
}

int main() {
    ::testing::InitGoogleTest();
    return RUN_ALL_TESTS();
}