update

Author: xiaoyaoworm

123_maxProfit.java

@@ -10,7 +10,7 @@ public int maxProfit(int[] prices) {
         //All dp[i][0] = 0 due to if you do i transaction but you don't see any stock there, profit is 0
         int res = 0;
         for(int i = 1; i <= k; i++){
-            int tmpMax = dp[i-1][0]-prices[0];
+            int tmpMax = dp[i-1][0]-prices[0];//tmpMax is the max value after last buy operation.
             for(int j = 1; j < prices.length; j++){
                 dp[i][j] = Math.max(dp[i][j-1], prices[j]+tmpMax);
                 tmpMax = Math.max(tmpMax, dp[i-1][j]-prices[j]);

414_thirdMax.java

@@ -0,0 +1,19 @@
+public class Solution {
+    public int thirdMax(int[] nums) {
+        if(nums == null || nums.length == 0) return 0;
+        PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
+        HashSet<Integer> set = new HashSet<Integer>();
+        for(int n: nums){
+            if(!set.contains(n)){
+                pq.offer(n);
+                set.add(n);
+                if(pq.size() > 3) pq.poll();
+            }
+        }
+        if(pq.size() == 3) return pq.poll();
+        while(pq.size() != 1){
+            pq.poll();
+        }
+        return pq.poll();
+    }
+}