https://leetcode.cn/problems/nth-magical-number

Author: masx200

README.md

@@ -45,6 +45,8 @@ Step 2. Add the dependency
 
 <summary>展开查看</summary>
 
+https://leetcode.cn/problems/nth-magical-number
+
 https://leetcode-cn.com/problems/target-sum/
 
 https://leetcode.cn/problems/soup-servings

nth-magical-number/index.ts

@@ -0,0 +1,31 @@
+export default function nthMagicalNumber(
+    n: number,
+    a: number,
+    b: number,
+): number {
+    const MOD = 1000000007;
+
+    const c = lcm(a, b);
+    const m = Math.floor(c / a) + Math.floor(c / b) - 1;
+    const r = n % m;
+    const res = (c * Math.floor(n / m)) % MOD;
+    if (r === 0) {
+        return res;
+    }
+    let addA = a,
+        addB = b;
+    for (let i = 0; i < r - 1; ++i) {
+        if (addA < addB) {
+            addA += a;
+        } else {
+            addB += b;
+        }
+    }
+    return (res + (Math.min(addA, addB) % MOD)) % MOD;
+}
+export function lcm(a: number, b: number) {
+    return Math.floor((a * b) / gcd(a, b));
+}
+export function gcd(a: number, b: number): number {
+    return b !== 0 ? gcd(b, a % b) : a;
+}

number-of-subarrays-with-lcm-equal-to-k/index.ts

@@ -4,24 +4,24 @@ export default function subarrayLCM(nums: number[], k: number): number {
 
     for (let i = 0; i < len; i++) {
         if (k % nums[i]) continue;
-        let lcm = nums[i];
+        let lcm_num = nums[i];
         for (let j = i; j < len; j++) {
             if (k % nums[j]) break;
-            lcm = getLCM(lcm, nums[j]);
+            lcm_num = lcm(lcm_num, nums[j]);
 
-            if (lcm === k) cnt += 1;
+            if (lcm_num === k) cnt += 1;
         }
     }
 
     return cnt;
 }
 
-function getGCD<T extends number | bigint>(a: T, b: T): T {
+function gcd<T extends number | bigint>(a: T, b: T): T {
     if (b == 0) return a;
-    return getGCD(b, (a % b) as T) as T;
+    return gcd(b, (a % b) as T) as T;
 }
 
-function getLCM<T extends number | bigint>(a: T, b: T): T {
-    return ((a * b) / getGCD(a, b)) as T;
+function lcm<T extends number | bigint>(a: T, b: T): T {
+    return ((a * b) / gcd(a, b)) as T;
 }
-export { getGCD, getLCM };
+export { gcd, lcm };