Points That Intersect With Cars

export function numberOfPoints(nums: number[][]): number {
  const prefix = new Array(102).fill(0);
  for (const [start, end] of nums) {
    prefix[start] += 1;
    prefix[end + 1] -= 1;
  }
 
  let answer = 0;
  let prefixSum = 0;
  prefix.forEach((value) => {
    prefixSum += value;
    if (0 < prefixSum) {
      answer += 1;
    }
  });
 
  return answer;
}