#0287

Minimum Spanning Tree Cost

HardDSA40 min25 XP

Problem

Given n nodes labeled 0 to n-1 and undirected weighted edges [u, v, w], return the minimum cost to connect every node, or -1 if impossible.

Why This Matters

MST problems combine greedy sorting with union-find, two patterns that often appear together.

Function Signature

def minimum_spanning_tree_cost(n, edges):

Examples

Example 1

Inputn = 4, edges = [[0,1,1],[1,2,2],[0,2,4],[2,3,1]]

Output4

Use edges 0-1, 2-3, and 1-2 for total cost 4.

Constraints

Return the exact requested value.
Handle edge cases cleanly.
Use the intended DSA pattern when brute force would scale poorly.

CodePython

def minimum_spanning_tree_cost(n, edges):
    """
    Input example: n = 4, edges = [[0,1,1],[1,2,2],[0,2,4],[2,3,1]]
    Return: 4
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return -1

def minimum_spanning_tree_cost(n, edges):
    """
    Input example: n = 4, edges = [[0,1,1],[1,2,2],[0,2,4],[2,3,1]]
    Return: 4
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return -1

Visible browser tests run here when available.

Testcases2 visible / 3 hidden categories

Connected graph

Input4 nodes

Expected4

The three cheapest non-cycling edges connect all nodes.

Disconnected graph

Input3 nodes one edge

Expected-1

Node 2 cannot be connected.

Hidden Test Categories

already tree-shaped graphduplicate edgescycle-heavy graph