Coin Change

Author: Sunjae95

coin-change/sunjae95.js

@@ -0,0 +1,90 @@
+/**
+ * @description
+ * brainstorming:
+ * 1. asc sort + division calculate
+ * 2. bfs + memoization
+ *
+ * strategy:
+ * bfs + memoization
+ *
+ * reason:
+ * Tried with brainstorming 1 but test case is false
+ *
+ * time complexity: O(n^k)
+ * space complexity: O(n)
+ */
+class Node {
+  constructor(val) {
+    this.value = val;
+    this.next = null;
+  }
+}
+
+class CustomQueue {
+  constructor() {
+    this.front = null;
+    this.rear = null;
+    this.size = 0;
+  }
+
+  push(val) {
+    const node = new Node(val);
+
+    if (this.size === 0) {
+      this.front = node;
+      this.rear = node;
+    } else {
+      this.rear.next = node;
+      this.rear = node;
+    }
+
+    this.size++;
+  }
+
+  pop() {
+    if (this.size === 0) return null;
+    const node = this.front;
+    this.front = this.front.next;
+    this.size--;
+    if (this.size === 0) this.rear = null;
+
+    return node.value;
+  }
+}
+
+var coinChange = function (coins, amount) {
+  const queue = new CustomQueue();
+  const memoSet = new Set();
+
+  if (amount === 0) return 0;
+
+  for (const coin of coins) {
+    if (amount === coin) return 1;
+
+    queue.push(coin);
+    memoSet.add(coin);
+  }
+
+  let count = 1;
+
+  while (queue.size) {
+    count++;
+    let depthSize = queue.size;
+
+    while (depthSize--) {
+      const sum = queue.pop();
+
+      for (const coin of coins) {
+        const nextSum = sum + coin;
+
+        if (memoSet.has(nextSum)) continue;
+        if (amount === nextSum) return count;
+        if (amount > nextSum) queue.push(nextSum);
+
+        memoSet.add(nextSum);
+      }
+    }
+  }
+
+  return -1;
+};