LEARNING JOURNAL

/**
 * Definition for BigArray.
 * class BigArray {
 *     constructor(elements: number[]);
 *     public at(index: number): number;
 *     public size(): number;
 * }
 */
function countBlocks(nums: BigArray | null): number {
  let iCur = 0, numBlocks = 0;
  const iMax = nums.size();

  while(iCur < iMax) {
      const nextI = getNextI(iCur, nums);
      iCur = nextI;
      numBlocks++;
  }

    return numBlocks;
};

function getNextI(iCur:number, nums:BigArray) {
    const val = nums.at(iCur);
    let lo = iCur, hi = nums.size() - 1;

    while(lo <= hi) {
        const midI = Math.floor((lo + hi)/2);

        const midVal = nums.at(midI);

        if(midVal !== val) {
            hi = midI - 1;
        }
        else {
            lo = midI + 1;
        }
    }

    return hi + 1;
}