update dp

Author: Fettes

DP/120.triangle.java

@@ -0,0 +1,40 @@
+/*
+ * @lc app=leetcode id=120 lang=java
+ *
+ * [120] Triangle
+ */
+
+// @lc code=start
+class Solution {
+    public int minimumTotal(List<List<Integer>> triangle) {
+        if (triangle.size() == 0 || triangle == null) {
+            return 0;
+        }
+
+        int n = triangle.size();
+        int[][] dp = new int[n][n];
+        //initialization
+        dp[0][0] = triangle.get(0).get(0);
+        int result = Integer.MAX_VALUE;
+
+        for (int i = 1; i < triangle.size(); i++) {
+            for (int j = 0; j <= i; j++) {
+                if (j == 0) {
+                    dp[i][j] = dp[i - 1][j] + triangle.get(i).get(j);
+                } else if (j == i) {
+                    dp[i][j] = dp[i - 1][j - 1] + triangle.get(i).get(j);
+                } else {
+                    dp[i][j] = Math.min(dp[i - 1][j - 1], dp[i - 1][j]) + triangle.get(i).get(j);
+                }
+            }
+        }
+        //find the minimum in the last row
+        for (int i = 0; i < n; i++) {
+            result = Math.min(result, dp[n - 1][i]);
+        }
+
+        return result;
+    }
+}
+// @lc code=end
+

DP/509.fibonacci-number.java

@@ -0,0 +1,23 @@
+/*
+ * @lc app=leetcode id=509 lang=java
+ *
+ * [509] Fibonacci Number
+ */
+
+// @lc code=start
+class Solution {
+    public int fib(int N) {
+        int[] dp = new int[N + 1];
+        if (N < 2) {
+            return N;
+        }
+        dp[0] = 0;
+        dp[1] = 1;
+        for (int i = 2; i <= N; i++) {
+            dp[i] = dp[i - 1] + dp[i - 2];
+        }
+        return dp[N];
+    }
+}
+// @lc code=end
+

README.md

@@ -108,9 +108,14 @@
 |----- |---------------- | --------------- |-------------- | ----------------- |
 #<span id="0315">0315 </span> | [Count of Smaller Numbers After Self](https://leetcode.com/problems/count-of-smaller-numbers-after-self/) | [View](Divide%20And%20Conquer/315.count-of-smaller-numbers-after-self.java) | Hard | [Count of Range Sum](#0327), [Queue Reconstruction by Height](#0406), [Reverse Pairs](#0493), [How Many Numbers Are Smaller Than the Current Number](#1365)
 #<span id="0493">0493 </span> | 
+
 ## DP (Dynamic Programming)
-|  #  | Title           |  Solution       | Difficulty    |
-|-----|---------------- | --------------- |------------- |
+|  ID  | Title           |  Solution       | Difficulty    | Similar Questions |
+|----- |---------------- | --------------- |-------------- | ----------------- |
+#<span id="0120">0120 </span> | [Triangle](https://leetcode.com/problems/triangle/) | [View](DP/120.triangle.java) | Medium | 
+#<span id="0509">0509 </span> | [Fibonacci Number](https://leetcode.com/problems/fibonacci-number/) | [View](DP/509.fibonacci-number.java) | Easy | [Climbing Stairs](#0070), [Split Array into Fibonacci Sequence](#0842), [Length of Longest Fibonacci Subsequence](#0873), [N-th Tribonacci Number](#1137)
+#<span id="1143">1143 </span> | [Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/) | [View]
+
 0322 | [Coin Change](https://leetcode.com/problems/coin-change/) | [View](./DP/CoinChange.cpp) | Medium |||
 0518 | [Coin Change 2](https://leetcode.com/problems/coin-change-2/) | [View](./DP/CoinChange2.cpp) | Medium |||
 0338 | [Counting Bits](https://leetcode.com/problems/counting-bits/) | [View](./DP/CountingBits.cpp) | Medium |||