overlappingTimeGroups.js

/**
Given inputs that represent overlapping times such as
[[6, 10], [7, 11], [8, 10], [11, 14], [12, 14], [15, 16]]
where each pair represents [startTime, endTime]
return an array that groups each time pair into an array of overlapping 
groups as such:
[
  [
    [6, 10],
    [7, 11],
    [8, 10]
  ],
  [
    [11, 14],
    [12, 14]
  ],
  [
    [15, 16]
  ]
]
*/

const overlappingTimeGroups = (inputTimes = []) => {
  if (inputTimes.length <= 1) {
    return inputTimes;
  }
  
  let newTimeGroups = [];
  let newTimeGroup = [];
  let lowerBoundTime = inputTimes[0][0];
  let upperBoundTime = inputTimes[0][1];
  
  
  for(let i = 0; i < inputTimes.length; i++) {
    const timePair = inputTimes[i];
    const startTime = timePair[0];
    const endTime = timePair[1];
    
    if (startTime < upperBoundTime) {
      newTimeGroup.push(timePair);
    } else {
      newTimeGroups.push(newTimeGroup);
      newTimeGroup = [timePair];
      lowerBoundTime = startTime;
      upperBoundTime = endTime;
    }
    
    if (i === inputTimes.length -1) {
      newTimeGroups.push(newTimeGroup);
    }
  }
  
  
  return newTimeGroups;
}


const inputTimes = [[6, 10], [7, 11], [8, 10], [11, 14], [12, 14], [15, 16]];
console.log(overlappingTimeGroups(inputTimes));