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feat: solve No.210,950
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BaffinLee committed Apr 10, 2024
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22 changes: 10 additions & 12 deletions 201-300/210. Course Schedule II.md
Original file line number Diff line number Diff line change
Expand Up @@ -74,22 +74,20 @@ var findOrder = function(numCourses, prerequisites) {
requiringMap[prerequisites[i][0]]++;
requiredByMap[prerequisites[i][1]].push(prerequisites[i][0]);
}
var queue = new MinPriorityQueue();
var queue = [];
for (var j = 0; j < numCourses; j++) {
queue.enqueue(j, requiringMap[j]);
requiringMap[j] === 0 && queue.push(j);
}
var res = [];
while (queue.size()) {
var item = queue.dequeue();
if (requiringMap[item.element] !== item.priority) continue;
if (item.priority !== 0) return [];
res.push(item.element);
for (var k = 0; k < requiredByMap[item.element].length; k++) {
requiringMap[requiredByMap[item.element][k]]--;
queue.enqueue(requiredByMap[item.element][k], requiringMap[requiredByMap[item.element][k]]);
while (queue.length) {
var course = queue.pop();
res.push(course);
for (var k = 0; k < requiredByMap[course].length; k++) {
requiringMap[requiredByMap[course][k]]--;
requiringMap[requiredByMap[course][k]] === 0 && queue.push(requiredByMap[course][k]);
}
}
return res;
return res.length === numCourses ? res : [];
};
```

Expand All @@ -99,5 +97,5 @@ nope.

**Complexity:**

* Time complexity : O(n * log(n)).
* Time complexity : O(n).
* Space complexity : O(n).
105 changes: 105 additions & 0 deletions 901-1000/950. Reveal Cards In Increasing Order.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,105 @@
# 950. Reveal Cards In Increasing Order

- Difficulty: Medium.
- Related Topics: Array, Queue, Sorting, Simulation.
- Similar Questions: .

## Problem

You are given an integer array `deck`. There is a deck of cards where every card has a unique integer. The integer on the `ith` card is `deck[i]`.

You can order the deck in any order you want. Initially, all the cards start face down (unrevealed) in one deck.

You will do the following steps repeatedly until all cards are revealed:



- Take the top card of the deck, reveal it, and take it out of the deck.

- If there are still cards in the deck then put the next top card of the deck at the bottom of the deck.

- If there are still unrevealed cards, go back to step 1. Otherwise, stop.


Return **an ordering of the deck that would reveal the cards in increasing order**.

**Note** that the first entry in the answer is considered to be the top of the deck.


Example 1:

```
Input: deck = [17,13,11,2,3,5,7]
Output: [2,13,3,11,5,17,7]
Explanation:
We get the deck in the order [17,13,11,2,3,5,7] (this order does not matter), and reorder it.
After reordering, the deck starts as [2,13,3,11,5,17,7], where 2 is the top of the deck.
We reveal 2, and move 13 to the bottom. The deck is now [3,11,5,17,7,13].
We reveal 3, and move 11 to the bottom. The deck is now [5,17,7,13,11].
We reveal 5, and move 17 to the bottom. The deck is now [7,13,11,17].
We reveal 7, and move 13 to the bottom. The deck is now [11,17,13].
We reveal 11, and move 17 to the bottom. The deck is now [13,17].
We reveal 13, and move 17 to the bottom. The deck is now [17].
We reveal 17.
Since all the cards revealed are in increasing order, the answer is correct.
```

Example 2:

```
Input: deck = [1,1000]
Output: [1,1000]
```


**Constraints:**



- `1 <= deck.length <= 1000`

- `1 <= deck[i] <= 106`

- All the values of `deck` are **unique**.



## Solution

```javascript
/**
* @param {number[]} deck
* @return {number[]}
*/
var deckRevealedIncreasing = function(deck) {
deck.sort((a, b) => a - b);
var res = Array(deck.length);
var i = 0;
var j = 0;
var skip = false;
while (i < deck.length) {
// find space for card
if (res[j] === undefined) {
// place card if it's not skip round
if (!skip) {
res[j] = deck[i];
i++;
}
// revert skip flag
skip = !skip;
}
// try next place
j = (j + 1) % deck.length;
}
return res;
};
```

**Explain:**

nope.

**Complexity:**

* Time complexity : O(n * log(n)).
* Space complexity : O(n).

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