AFFILIATE LINKS
Great resource I use to learn algorithms.
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Here is the full implementation.
/*
The key is to use two pointers, one for the beginning, and
one for the end. Switch the letters while start > end
*/
let reverseString = function(s) {
let start = 0;
let end = s.length - 1;
/* this loop references two letters at the same time. it starts with the first
and last letters and moves inward */
while (start < end) {
let tempFirst = s[start];
s[start] = s[end];
s[end] = tempFirst;
start++;
end--;
}
}