描述
Given a 0-indexed string word and a character ch, reverse the segment of word that starts at index 0 and ends at the index of the first occurrence of ch (inclusive). If the character ch does not exist in word, do nothing.
- For example, if word = “abcdefd” and ch = “d”, then you should reverse the segment that starts at 0 and ends at 3 (inclusive). The resulting string will be “dcbaefd”.
Return the resulting string.
测试用例
Input: word = "abcdefd", ch = "d"
Output: "dcbaefd"
Explanation: The first occurrence of "d" is at index 3.
Reverse the part of word from 0 to 3 (inclusive), the resulting string is "dcbaefd".题解
/**
* @param {string} word
* @param {character} ch
* @return {string}
*/
var reversePrefix = function(word, ch) {
let _num = -1; // the index of ch
let i = 0;
word = word.split('');
while(i < word.length) {
if(word[i] === ch) {
_num = i;
break;
}
i++;
}
for(let i = 0; i < _num / 2; i++) {
let temp = word[i];
word[i] = word[_num - i];
word[_num - i] = temp;
}
return word.join('');
};结果
Accepted
112/112 cases passed (76 ms)
Your runtime beats 60.98 % of javascript submissions
Your memory usage beats 46.34 % of javascript submissions (39 MB)
