algorithm001 · luckypeak · May 19, 2019
diff --git a/Week_04/id_124/LeetCode_169_124.java b/Week_04/id_124/LeetCode_169_124.java
@@ -0,0 +1,34 @@
+import java.util.List;
+
+public class MajorityElement {
+
+    public int majorityElement(int[] nums) {
+        int cnt = 1;
+        int result = nums[0];
+        for (int i = 1;  i < nums.length ; i++){
+            if (nums[i] == result){
+                cnt ++;
+                if (cnt > nums.length /2){
+                    return result;
+                }
+            }else {
+                cnt --;
+            }
+            if (cnt <= 0 ){
+                result = nums[i];
+                cnt = 1;
+            }
+        }
+
+        return result;
+    }
+
+    public List<Integer> majorityElement2(int[] nums) {
+
+        return null;
+    }
+
+    public static void main(String[] args) {
+
+    }
+}
diff --git a/Week_04/id_124/LeetCode_746_124.java b/Week_04/id_124/LeetCode_746_124.java
@@ -0,0 +1,19 @@
+public class MinCostClimbingStairs {
+
+    public int minCostClimbingStairs(int[] cost) {
+        if (cost.length == 2) {
+            return Math.min(cost[0], cost[1]);
+        }
+        int[] dp = new int[cost.length + 1];
+        dp[0] = cost[0];
+        dp[1] = cost[1];
+        for (int i = 2; i < cost.length; i++) {
+            dp[i] = Math.min(dp[i - 2], dp[i - 1]) + cost[i];
+        }
+        return Math.min(dp[cost.length - 1], dp[cost.length - 2]);
+    }
+
+
+
+
+}