From a0a413fce57218cfd485f87325f3e2f99bc8770f Mon Sep 17 00:00:00 2001
From: chenzhengwei <chenzhengwei@baidu.com>
Date: Thu, 16 Feb 2017 14:37:27 +0800
Subject: [PATCH] a416

---
 README.md               |  2 ++
 Solution/401-450/416.md | 46 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 Solution/401-450/416.md

diff --git a/README.md b/README.md
index 5a8a439..68daa19 100644
--- a/README.md
+++ b/README.md
@@ -116,3 +116,5 @@ leetcode 题解
 
 [383. Ransom Note](Solution/351-400/383.md)
 
+[416. Partition Equal Subset Sum](Solution/401-450/416.md)
+
diff --git a/Solution/401-450/416.md b/Solution/401-450/416.md
new file mode 100644
index 0000000..1940fad
--- /dev/null
+++ b/Solution/401-450/416.md
@@ -0,0 +1,46 @@
+#416. Partition Equal Subset Sum
+[题目链接](https://leetcode.com/problems/partition-equal-subset-sum/)
+```java
+public class Solution {
+    /*
+        转化为01背包问题
+     */
+    public boolean canPartition(int[] nums) {
+        // 首先判断一些特殊情况
+        int sum = 0;
+        for (int i = 0; i < nums.length; i++) {
+            sum += nums[i];
+        }
+        if (sum % 2 == 1) {
+            return false;
+        }
+        int target = sum / 2;
+        for (int i = 0; i < nums.length; i++) {
+            if (nums[i] > target) {
+                return false;
+            } else if (nums[i] == target) {
+                return true;
+            }
+        }
+
+        // 如果仍无法判断，转化为01背包问题
+        int len = nums.length;
+        boolean[][] dp = new boolean[len + 1][target + 1];
+        for (int i = 0; i < dp.length; i++) {
+            Arrays.fill(dp[i], false);
+        }
+        for (int i = 0; i < len + 1; i++) {
+            dp[i][0] = true;
+        }
+        for (int i = 1; i < len + 1; i++) {
+            for (int j = 1; j < target + 1; j++) {
+                dp[i][j] = dp[i - 1][j];
+                if (j >= nums[i - 1]) {
+                    dp[i][j] = dp[i][j] || dp[i - 1][j - nums[i - 1]];
+                }
+            }
+        }
+        return dp[len][target];
+    }
+}
+```
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