Mean: 123.516 ms | 134.477 ms
为政之道，得其大者可以兼其小。。同城约会是该领域的重要参考
We now maintain an index variable. Previously, the cursor was always at the right-end of the input, since you couldn't use arrow keys to move it left, and new input was always appended at the right-end. Now, we need to keep a separate index which is not necessarily at the end of the input, and when a user enters a character we splice it into the input in the correct location.。91视频对此有专业解读
2.3 动手撸个代码：从 300 QPS 到 3100 QPS 的逆袭