Leetcode 1101 The Earliest Moment When Everyone Become Friends

leetcode1101

function earliestAcq(logs: number[][], n: number): number {

    logs.sort((a:number[], b:number[]) => {
       return (a[0] - b[0]);
    });

    let mapOfSets = new Map();
    
    // put every friend ID into its own individual set - O(n)
    for (let i = 0; i < n; i++) {
        let individualSet = new Set();
        individualSet.add(i);
        mapOfSets.set(i, individualSet);
    }
    
    // now every friend is its own set in the map 
    console.log(mapOfSets);
    
    // step through the logs and join the sets as matches are encountered 
    for (let i = 0; i < logs.length; i++) {
        let friendA = logs[i][1];
        let friendB = logs[i][2];
        
        let setA = mapOfSets.get(friendA);
        let setB = mapOfSets.get(friendB);
        
        if (setA != setB) {
            // join the two sets
            for (let friend of setB) {
                // add all the friends from setB to setA
                setA.add(friend);
                
                // update map of sets such that setA is pointed at by each friend originally from B
                mapOfSets.set(friend, setA);
            }
            
            if (setA.size === n) {
                // every friend is now accounted for in set A
                // return the timestamp where this was achieved
                return logs[i][0];
            }
        }
    }
    
    return -1;
};