From c7ca47a20eb87ae1ce1ec36e6333c5d5ebdfed68 Mon Sep 17 00:00:00 2001
From: dehuab <dehuab@tujia.com>
Date: Sat, 11 May 2019 22:59:43 +0800
Subject: [PATCH] week4 homework

---
 Week_04/id_36/LeetCode_169_036.java | 26 ++++++++++++++++++++++++++
 Week_04/id_36/LeetCode_746_036.java | 29 +++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 Week_04/id_36/LeetCode_169_036.java
 create mode 100644 Week_04/id_36/LeetCode_746_036.java

diff --git a/Week_04/id_36/LeetCode_169_036.java b/Week_04/id_36/LeetCode_169_036.java
new file mode 100644
index 00000000..603033ec
--- /dev/null
+++ b/Week_04/id_36/LeetCode_169_036.java
@@ -0,0 +1,26 @@
+package com.potato.leetcode;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class LeetCode_169_036 {
+    public int majorityElement(int[] nums) {
+        Map<Integer, Integer> map = new HashMap<>();
+        int n = nums.length;
+        int count = 0;
+        for (int i : nums) {
+            if (map.containsKey(i)) {
+                count = map.get(i) + 1;
+            } else {
+                count = 1;
+            }
+
+            if (count > n / 2) {
+                return i;
+            }
+
+            map.put(i, count);
+        }
+        return -1;
+    }
+}
diff --git a/Week_04/id_36/LeetCode_746_036.java b/Week_04/id_36/LeetCode_746_036.java
new file mode 100644
index 00000000..ea18d239
--- /dev/null
+++ b/Week_04/id_36/LeetCode_746_036.java
@@ -0,0 +1,29 @@
+package com.potato.leetcode;
+
+public class LeetCode_746_036 {
+    public int minCostClimbingStairs(int[] cost) {
+        if (cost == null) {
+            return 0;
+        }
+
+        if (cost.length == 1) {
+            return cost[0];
+        }
+
+        if (cost.length == 2) {
+            return Math.min(cost[0], cost[1]);
+        }
+
+        int[] tmp = new int[2];
+        tmp[0] = cost[0];
+        tmp[1] = cost[1];
+
+        int min = 0;
+        for (int i = 2; i < cost.length; i++) {
+            min = Math.min(tmp[0], tmp[1]);
+            tmp[0] = tmp[1];
+            tmp[1] = min + cost[i];
+        }
+        return Math.min(tmp[0], tmp[1]);
+    }
+}