646-maximum-length-of-pair-chain.js

/**
 * @param {number[][]} pairs
 * @return {number}
 */
var findLongestChain = function (pairs) {
  pairs.sort((a, b) => a[1] - b[1]);

  let cur = Number.MIN_SAFE_INTEGER,
    ans = 0;

  for (const [start, end] of pairs) {
    if (cur < start) {
      cur = end;
      ans++;
    }
  }

  return ans;
};