字符串 - 反转字符串 II

541. 反转字符串 II

方法一：模拟（reverse方法分开写）

/*** @param {string} s* @param {number} k* @return {string}*/
var reverseStr = function(s, k) {const n = s.length;const arr = Array.from(s);for (let i = 0; i < n; i += 2 * k) {reverse(arr, i, Math.min(i + k, n) - 1);}return arr.join('');
};const reverse = (arr, left, right) => {while (left < right) {const temp = arr[left];arr[left] = arr[right];arr[right] = temp;left++;right--;}
}

方法二：reverse写一起

/*** @param {string} s* @param {number} k* @return {string}*/
var reverseStr = function(s, k) {const len = s.length;let resArr = s.split("");for (let i = 0; i < len; i += 2 * k) {  // 每隔2k个字符的前k个字符进行反转let l = i - 1, r = i + k > len ? len : i + k;while (++l < --r) [resArr[l], resArr[r]] = [resArr[r], resArr[l]];}return resArr.join("");
};