russianDollEnvelopes.js

/**
 * @param {number[][]} envelopes
 * @return {number}
 */
var maxEnvelopes = function(envelopes) {
    
    let maxNested = 0;

    let sorted = envelopes.slice(0).sort((a,b) => {
        return (b[0] + b[1] - a[0] - a[1])
    }) 
    
    const isNestable = function(a, b) {
      console.log(a, b, b[0] < a[0] && b[1] < a[1])
        return b[0] < a[0] && b[1] < a[1]
    }
    
    const explore = function(index, count) {
        if (count > maxNested) {
            maxNested = count;
        }
        
        for (let j = index; j < sorted.length; j++) {
            if (isNestable(sorted[index], sorted[j])) {
                explore(j, count + 1);
            }
        }
    }
    
    for (let i = 0; i < sorted.length - maxNested; i++) {
        explore(i, 1)
    }
    return maxNested     
};