746. Min Cost Climbing Stairs (#58)

Author: Kohei Asai

solutions/minCostClimbingStairs.test.ts

@@ -0,0 +1,11 @@
+import minCostClimbingStairs from "./minCostClimbingStairs";
+
+describe("746. Min Cost Climbing Stairs", () => {
+  test("#1", () => {
+    expect(minCostClimbingStairs([10, 15, 20])).toBe(15);
+  });
+
+  test("#2", () => {
+    expect(minCostClimbingStairs([1, 100, 1, 1, 1, 100, 1, 1, 100, 1])).toBe(6);
+  });
+});

solutions/minCostClimbingStairs.ts

@@ -0,0 +1,15 @@
+// 746. Min Cost Climbing Stairs
+// https://leetcode.com/problems/min-cost-climbing-stairs/
+function minCostClimbingStairs(costs: number[]): number {
+  // this is dynamic programming.
+  // see https://github.com/axross/leetcode-typescript/pull/58
+  const dp = new Map([[-2, 0], [-1, 0]]);
+
+  for (let i = 0; i <= costs.length; ++i) {
+    dp.set(i, Math.min(dp.get(i - 2)!, dp.get(i - 1)!) + (costs[i] || 0));
+  }
+
+  return dp.get(costs.length)!;
+}
+
+export default minCostClimbingStairs;