LeetCode[416] Partition Equal Subset Sum

Given a non-empty array containing only positive integers, find if the array can be partitioned into two subsets such that the sum of elements in both subsets is equal.

Note:
Both the array size and each of the array element will not exceed 100.

Example 1:

Input: [1, 5, 11, 5]Output: trueExplanation: The array can be partitioned as [1, 5, 5] and [11].

Example 2:

Input: [1, 2, 3, 5]Output: falseExplanation: The array cannot be partitioned into equal sum subsets.

背包问题，而且元素不可重复。注意两个for循环的写法

class Solution {public:bool canPartition(vector<int>& nums) {int sum = 0;int n = nums.size();for (int i = 0; i < n; ++i) {sum += nums[i];}if ((sum & 1) == 1) return false;sum = sum >> 1;vector<int> dp(sum + 1, 0);for (int i = 0; i < n; ++i) {              for (int j = sum; j >= 1; --j) {                  if (j >= nums[i]) {                      dp[j] = max(dp[j], nums[i] + dp[j - nums[i]]);                  }              }          } return dp[sum] == sum;}};