From e9c4d54f537a1c42f71b5651bfc4baa0cd1a51e8 Mon Sep 17 00:00:00 2001
From: fw_qaq <fwqaaq@gmail.com>
Date: Thu, 13 Apr 2023 12:28:51 +0800
Subject: [PATCH] =?UTF-8?q?Update=200746.=E4=BD=BF=E7=94=A8=E6=9C=80?=
 =?UTF-8?q?=E5=B0=8F=E8=8A=B1=E8=B4=B9=E7=88=AC=E6=A5=BC=E6=A2=AF.md?=
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---
 problems/0746.使用最小花费爬楼梯.md | 37 ++++++++++++++++-------------
 1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/problems/0746.使用最小花费爬楼梯.md b/problems/0746.使用最小花费爬楼梯.md
index 98a58c12..3d014858 100644
--- a/problems/0746.使用最小花费爬楼梯.md
+++ b/problems/0746.使用最小花费爬楼梯.md
@@ -330,22 +330,27 @@ var minCostClimbingStairs = function(cost) {
 
 ```typescript
 function minCostClimbingStairs(cost: number[]): number {
-    /**
-        dp[i]: 走到第i阶需要花费的最少金钱
-        dp[0]: 0;
-        dp[1]: 0;
-        ...
-        dp[i]: min(dp[i - 1] + cost[i - 1], dp[i - 2] + cost[i - 2]);
-     */
-    const dp = [];
-    const length = cost.length;
-    dp[0] = 0;
-    dp[1] = 0;
-    for (let i = 2; i <= length; i++) {
-        dp[i] = Math.min(dp[i - 1] + cost[i - 1], dp[i - 2] + cost[i - 2]);
-    }
-    return dp[length];
-};
+  const dp = [0, 0]
+  for (let i = 2; i <= cost.length; i++) {
+    dp[i] = Math.min(dp[i - 1] + cost[i - 1], dp[i - 2] + cost[i - 2])
+  }
+  return dp[cost.length]
+}
+```
+
+不使用 dp 数组
+
+```typescript
+function minCostClimbingStairs(cost: number[]): number {
+  let dp_before = 0,
+    dp_after = 0
+  for (let i = 2; i <= cost.length; i++) {
+    let dpi = Math.min(dp_before + cost[i - 2], dp_after + cost[i - 1])
+    dp_before = dp_after
+    dp_after = dpi
+  }
+  return dp_after
+}
 ```
 
 ### Rust