js-02-merge-intervals

1.000

10/10 tests· algorithms

Proposed solution

```js
export function mergeIntervals(intervals) {
  // Handle empty input
  if (intervals.length === 0) {
    return [];
  }
  
  // Sort intervals by start time
  const sorted = [...intervals].sort((a, b) => a[0] - b[0]);
  
  // Merge overlapping intervals
  const merged = [sorted[0]];
  
  for (let i = 1; i < sorted.length; i++) {
    const current = sorted[i];
    const lastMerged = merged[merged.length - 1];
    
    // Check if current interval overlaps with the last merged interval
    if (current[0] <= lastMerged[1]) {
      // Merge them by updating the end time of the last merged interval
      lastMerged[1] = Math.max(lastMerged[1], current[1]);
    } else {
      // No overlap, add current interval to merged array
      merged.push(current);
    }
  }
  
  return merged;
}
```

Test output (stdout)

TAP version 13
# Subtest: empty input returns empty array
ok 1 - empty input returns empty array
  ---
  duration_ms: 0.590393
  type: 'test'
  ...
# Subtest: single interval is returned unchanged
ok 2 - single interval is returned unchanged
  ---
  duration_ms: 0.101541
  type: 'test'
  ...
# Subtest: unsorted disjoint input is sorted
ok 3 - unsorted disjoint input is sorted
  ---
  duration_ms: 0.06297
  type: 'test'
  ...
# Subtest: overlapping intervals merge
ok 4 - overlapping intervals merge
  ---
  duration_ms: 0.431923
  type: 'test'
  ...
# Subtest: touching endpoints merge
ok 5 - touching endpoints merge
  ---
  duration_ms: 0.06675
  type: 'test'
  ...
# Subtest: containment keeps the wider interval
ok 6 - containment keeps the wider interval
  ---
  duration_ms: 0.050321
  type: 'test'
  ...
# Subtest: disjoint intervals are left separate
ok 7 - disjoint intervals are left separate
  ---
  duration_ms: 0.05269
  type: 'test'
  ...
# Subtest: duplicates collapse to one
ok 8 - duplicates collapse to one
  ---
  duration_ms: 0.04382
  type: 'test'
  ...
# Subtest: mixed unsorted overlapping and disjoint
ok 9 - mixed unsorted overlapping and disjoint
  ---
  duration_ms: 0.060631
  type: 'test'
  ...
# Subtest: the input array is not mutated
ok 10 - the input array is not mutated
  ---
  duration_ms: 0.112201
  type: 'test'
  ...
1..10
# tests 10
# suites 0
# pass 10
# fail 0
# cancelled 0
# skipped 0
# todo 0
# duration_ms 30.079493

System prompt

You are an expert programmer. Solve the task exactly as specified. Output your solution as fenced code blocks using the required file name(s) and the exact function/type signatures requested. Prefer correctness; do not include prose outside code unless asked.