Problems › TypeScript › data
The second highest number
A leaderboard shows only the top name, but the report also wants the runner-up.
- Run the equal values together: 10, 10, 9 has a second largest of 9.
- Fewer than two distinct values gives -1.
secondLargest(values: list<int>) → int
Where you start
function secondLargest(values: number[]): number {
}Worked examples
| Call | Result |
|---|---|
secondLargest([3,1,2]) | 2 |
secondLargest([10,10,9]) | 9 |
secondLargest([4,1,4,2,3]) | 3 |
secondLargest([5]) | -1 |
Hint
Walk once keeping the two best so far, and ignore a value equal to the current best.
Reference solution in TypeScript
function secondLargest(values: number[]): number {
let found = false;
let second = 0;
let best = 0;
let started = false;
for (const v of values) {
if (!started) {
best = v;
started = true;
continue;
}
if (v > best) {
second = best;
found = true;
best = v;
} else if (v < best) {
if (!found || v > second) {
second = v;
found = true;
}
}
}
return found ? second : -1;
}