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6 files changed

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lines changed

‎.gitignore

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.DS_Store
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es.log

‎947/my_solution.js

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class UnionFind {
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constructor() {
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this.parent = new Map();
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this.rank = new Map();
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}
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find(x) {
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if (this.parent.get(x) !== x) {
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this.parent.set(x, this.find(this.parent.get(x))); // Path compression
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}
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return this.parent.get(x);
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}
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union(x, y) {
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let rootX = this.find(x);
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let rootY = this.find(y);
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if (rootX !== rootY) {
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let rankX = this.rank.get(rootX) || 1;
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let rankY = this.rank.get(rootY) || 1;
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if (rankX > rankY) {
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this.parent.set(rootY, rootX);
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} else if (rankX < rankY) {
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this.parent.set(rootX, rootY);
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} else {
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this.parent.set(rootY, rootX);
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this.rank.set(rootX, rankX + 1);
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}
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}
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}
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add(x) {
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if (!this.parent.has(x)) {
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this.parent.set(x, x);
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this.rank.set(x, 1);
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}
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}
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}
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/**
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* @param {number[][]} stones
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* @return {number}
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*/
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var removeStones = function (stones) {
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const uf = new UnionFind();
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// console.log("uf", uf);
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// Use separate identifiers for rows and columns by adding a large constant to column identifiers
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for (let [xs, ys] of stones) {
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uf.add(xs); // Add row identifier
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uf.add(ys + 10001); // Add column identifier, shifted to avoid collision with row IDs
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uf.union(xs, ys + 10001); // Union row and column
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console.log("each loop\n",uf);
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}
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console.log("post loop\n",uf);
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const uniqueParents = new Set();
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for (let [xs, ys] of stones) {
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uniqueParents.add(uf.find(xs));
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}
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return stones.length - uniqueParents.size;
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};
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// Test Case 1: Simple connected component
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let stones1 = [[0, 0], [0, 1], [1, 0], [1, 2], [2, 1], [2, 2]];
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console.log(removeStones(stones1)); // Expected output: 5
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// // Test Case 2: No stones
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// let stones2 = [];
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// console.log(removeStones(stones2)); // Expected output: 0
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//
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// // Test Case 3: Single stone
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// let stones3 = [[0, 0]];
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// console.log(removeStones(stones3)); // Expected output: 0
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//
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// // Test Case 4: Two disconnected stones
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// let stones4 = [[0, 0], [1, 1]];
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// console.log(removeStones(stones4)); // Expected output: 0
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//
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// // Test Case 5: Multiple stones forming a complex structure
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// let stones5 = [[0, 0], [0, 2], [1, 1], [2, 0], [2, 2]];
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// console.log(removeStones(stones5)); // Expected output: 3

‎947/solution.js

Whitespace-only changes.

‎947/union_find.js

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class UnionFind {
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constructor() {
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this.parent = new Map();
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this.rank = new Map();
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console.log("Initial parent map:", JSON.stringify([...this.parent]));
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console.log("Initial rank map:", JSON.stringify([...this.rank]));
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}
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add(x) {
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if (this.parent.has(x)) return;
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this.parent.set(x, x);
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this.rank.set(x, 1);
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}
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find(x) {
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console.log(`~~> Find(${x})`);
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// Find the root of the element x
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if (this.parent.get(x) !== x) {
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console.log(`Path compression for element ${x}`);
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this.parent.set(x, this.find(this.parent.get(x))); // Path compression
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}
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console.log(`Find(${x}) -> Root is ${this.parent.get(x)}`);
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return this.parent.get(x);
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}
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union(x, y) {
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console.log(`\nUnion(${x}, ${y})`);
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this.add(x);
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this.add(y);
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// Find the roots of x and y
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console.log(`~> before find:`, JSON.stringify([...this.parent]));
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let rootX = this.find(x);
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let rootY = this.find(y);
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if (rootX !== rootY) {
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console.log(`Union(${x}, ${y}) -> Already in the same set`);
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return;
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}
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let rankX = this.rank.get(rootX);
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let rankY = this.rank.get(rootY);
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console.log(`rootX: ${rootX}, \nrootY: ${rootY}, \nrankX: ${rankX}, \nrankY: ${rankY}`);
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console.log(`~~~> after find:`, JSON.stringify([...this.parent]));
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// If they have different roots, perform union
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if (rankX > rankY) {
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console.log(`(x <- y) -> Root of ${y} (root ${rootY}) attached to root ${rootX}`);
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this.parent.set(rootY, rootX);
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} else if (rankX < rankY) {
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console.log(`(x -> y) -> Root of ${x} (root ${rootX}) attached to root ${rootY}`);
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this.parent.set(rootX, rootY);
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} else {
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console.log(`(x <- y) -> Roots are equal, root ${rootY} attached to root ${rootX}`);
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this.parent.set(rootY, rootX);
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this.rank.set(rootX, rankX + 1); // ONLY increase the rank of the new root
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}
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console.log(`parent: ${JSON.stringify([...this.parent])}`);
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console.log(`rank: ${JSON.stringify([...this.rank])}`);
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}
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}
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// Create an instance of UnionFind with 8 elements (0 through 7)
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let uf = new UnionFind();
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// Test Cases
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console.log("\nTest Case 1: Union operations");
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// uf.union(1, 2);
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// uf.union(2, 3);
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uf.union(0, 0);
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uf.union(0, 1);
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uf.union(1, 0);
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uf.union(1, 2);
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uf.union(2, 1);
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uf.union(2, 2);
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// uf.union(4, 5);
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// uf.union(6, 7);
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// uf.union(5, 6);
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// uf.union(3, 7); // This will connect two previously separate sets
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// // console.log("\n--> size", uf.size());
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//
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// console.log("\nTest Case 2: Find operations");
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// console.log("\n- Find(1):", uf.find(1)); // Should compress path for 1 -> 2 -> 3 -> root
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// console.log("\n- Find(2):", uf.find(2)); // Already compressed
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// console.log("\n- Find(5):", uf.find(5)); // Should show the root of the 4-5-6-7 component
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// console.log("Find(8):", uf.find(8)); // 8 should be its own root (no connections yet)
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//
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// console.log("\nTest Case 3: Additional Unions and Finds");
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// uf.union(8, 9);
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// console.log("Find(9):", uf.find(9)); // Should point to root after union with 8
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// uf.union(3, 8); // This will connect the 1-2-3-7-6-5-4 set with 8-9
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// console.log("Find(9):", uf.find(9)); // Should now point to the root of the entire connected set
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// console.log("Final parent array:", uf.parent);
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// console.log("Final rank array:", uf.rank);

‎README.md

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<!--
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NOTE: JS IS HERE
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-->
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```ssh
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chapter=743 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
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```sh
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chapter=947 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
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```
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> then you can use `x` for quick debug.
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‎test.js

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// console.log(Array(26).fill(0));
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let x = [1, 2, 3]
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// let x = [1, 2, 3]
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// console.log(x)
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// console.log("splicing index 1 from x")
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// x.splice(1, 1)
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// console.log(x)
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let x = 1;
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console.log("x")
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console.log(x)
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console.log("splicing index 1 from x")
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x.splice(1, 1)
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x = [1, 2, 3];
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console.log("> x")
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console.log(x)

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