Merge pull request algorithm001#661 from yxs354/master

submit week 04 assignment

Author: GeekUniversity

Week_04/id_44/LeetCode_169_044.java

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+public class LeetCode_169_044 {
+    public int majorityElement(int[] nums) {
+        return divc(nums, 0, nums.length - 1); 
+    }
+    private int divc(int[] nums, int l, int r){
+        if(l == r)
+            return nums[l];
+        int mid = l + (r - l)/2;
+        int ls = divc(nums, l, mid);
+        int rs = divc(nums, mid+1, r);
+        if(ls == rs)
+            return ls;
+        int c1 = 0, c2 = 0;
+        for(int i = l; i <= r; i++){
+            if(nums[i] == ls) c1++;
+            if(nums[i] == rs) c2++;
+        }
+        return c1 > c2 ? ls : rs;
+    }
+}

Week_04/id_44/LeetCode_746_044.java

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+class LeetCode_746_044 {
+    public int minCostClimbingStairs(int[] cost) {
+        int step[] = new int[1024];
+        step[0] = 0;
+        step[1] = 0;
+        if (cost.length == 0) {
+            return 0;
+        }
+        if (cost.length == 1) {
+            return cost[0];
+        }
+        if (cost.length == 2) {
+            return Math.min(cost[0], cost[1]);
+        }
+        for (int i = 2; i <= cost.length; i++) {
+            step[i] = Math.min(step[i - 1] + cost[i - 1], step[i - 2] + cost[i - 2]);
+        }
+        return step[cost.length];
+    }
+}