Merge Intervals

mergeIntervals.js

/**
 * @param {number[][]} intervals
 * @return {number[][]}
 */
var merge = function(intervals) {
    let temp = [];
    intervals.sort((a, b) => a[0] - b[0])
    for(let i=0; i<intervals.length - 1; i++) {
        if(intervals[i][1] >= intervals[i+1][0]) {
            temp = intervals.splice(i+1, 1);
            if(intervals[i][1] <= temp[0][1]) {
                intervals[i][1] = temp[0][1];
            }
            if(intervals[i][0] >= temp[0][0]) {
                intervals[i][0] = temp[0][0]
            }
            i--;
        }
    }
    return intervals;
};

// Sort the array (nlog(n))
// run a loop from the start to n-1
// if the current element last value is greater then the second element first value, then remove the second element and store it in temp
// if current interval last element is lesser then the current interval last element becomes temp variable first element 
// do the same for the first element

// time - O(nlog(n))
// space - O(1)