add

xutao · xutao · commit ac932bdd1340 · 2020-07-20T00:30:09.000+08:00
diff --git a/Week06/LongestValidParentheses.java b/Week06/LongestValidParentheses.java
@@ -0,0 +1,17 @@
+public class LongestValidParentheses {
+    public int longestValidParentheses(String s) {
+        int maxans = 0;
+        int dp[] = new int[s.length()];
+        for (int i = 1; i < s.length(); i++) {
+            if (s.charAt(i) == ')') {
+                if (s.charAt(i - 1) == '(') {
+                    dp[i] = (i >= 2 ? dp[i - 2] : 0) + 2;
+                } else if (i - dp[i - 1] > 0 && s.charAt(i - dp[i - 1] - 1) == '(') {
+                    dp[i] = dp[i - 1] + ((i - dp[i - 1]) >= 2 ? dp[i - dp[i - 1] - 2] : 0) + 2;
+                }
+                maxans = Math.max(maxans, dp[i]);
+            }
+        }
+        return maxans;
+    }
+}
diff --git a/Week06/MinPathSum.java b/Week06/MinPathSum.java
@@ -0,0 +1,15 @@
+public class MinPathSum {
+    public int minPathSum(int[][] grid) {
+        for (int i = grid.length - 1; i >= 0; i--) {
+            for (int j = grid[0].length - 1; j >= 0; j--) {
+                if(i == grid.length - 1 && j != grid[0].length - 1)
+                    grid[i][j] = grid[i][j] +  grid[i][j + 1];
+                else if(j == grid[0].length - 1 && i != grid.length - 1)
+                    grid[i][j] = grid[i][j] + grid[i + 1][j];
+                else if(j != grid[0].length - 1 && i != grid.length - 1)
+                    grid[i][j] = grid[i][j] + Math.min(grid[i + 1][j],grid[i][j + 1]);
+            }
+        }
+        return grid[0][0];
+    }
+}
diff --git a/Week06/NOTE.md b/Week06/NOTE.md
@@ -1 +1,5 @@
-学习笔记
+### 总结：
+- 1.动态规划好难，从一位到二位再到多维，还是要打破思维定式。
+- 2.涉及了很多之前讲过的内容，如果基础不牢靠，看这期Dp就有点吃力。
+- 3.总之还是要多练习动态规划的题目，尝试由底到顶的思维模式。
+- 4.课后习题有点做不完，难度上升了，要花更多的时间去攻克难题了。
