Dwarfs standing on the shoulders of giants - Solution

dwarfs.js

/**
 * Auto-generated code below aims at helping you parse
 * the standard input according to the problem statement.
 **/

var graph = [];
var n = parseInt(readline()); // the number of adjacency relations
for (var i = 0; i < n; i++) {
    var inputs = readline().split(' ');
    var xi = parseInt(inputs[0]); // the ID of a person which is adjacent to yi
    var yi = parseInt(inputs[1]); // the ID of a person which is adjacent to xi
    if (!graph[xi]) {
        graph[xi] = { data: xi, edges: [], depth: 1};
    }
    if (!graph[yi]) {
        graph[yi] = { data: yi, edges: [], depth: 1};
    }
    printErr(xi+'---'+yi);
    graph[xi].edges.push(graph[yi])
}

/*//non-optimized solution
function explore_graph(node){
  cur_node = graph[node];
  for(var i in cur_node.edges){
    if(cur_node.depth < (graph[cur_node.edges[i]].depth + 1)){
        graph[node].depth +=1;
        explore_graph(node);
    } 
  }
}
*/

function explore(n, d) { 
    if (!n.edges.length) {
        return d;
    } else {
        var max = 0;
        n.edges.map(function(w) {   
            var result = explore(w, d + 1);
            graph[w.data].depth = result;
            if (result > max) {
                max = result;                  
            }
        });
       return max;
    }
}

graph.map(function(w) {
    explore(w, 1);
});

// Write an action using print()
// To debug: printErr('Debug messages...');

print(Math.max(...graph.map(w => w.depth).filter(n => true)));