In here, I would like to discuss the dynamic set in Leetcode 128 Longest Consecutive Sequence.
This is my solution:
- Put all numbers into set.
- The find the first number of each sequence. The first number is the number without any previous number (n-1) in the set.
- Loop through the next number (n+1). And find out the max count. (Remove the current number from set in order to iterate it again.)
var longestConsecutive = function(nums) {
let set = new Set(nums);
let maxLen = 0;
function next(num) {
if (set.has(num)) {
//set.delete(num);
return next(num + 1) + 1;
} else {
return 0;
}
}
console.log(set);
for (let num of nums) {
//console.log(num);
let pre = num - 1;
if (!set.has(pre)) {
let len = next(num+1) + 1;
if (len > maxLen) {
maxLen = len;
}
}
}
return maxLen;
};
The particular I would discuss is
Remove the current number from set in order to iterate it again.
set.delete(num)
I would say that can be optimize performance. However, base on the leetcode submission result, dynamic changing set is actually a performance penalty.
