LN : leetcode 416 Partition Equal Subset Sum
阿新 • • 發佈:2017-12-18
con not 表數 tco -- 我們 tro -m accepted
lc 416 Partition Equal Subset Sum
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:
Each of the array element will not exceed 100.
The array size will not exceed 200.
Example 1:
Input: [1, 5, 11, 5]
Output: true
Explanation: The array can be partitioned as [1, 5, 5] and [11].
Example 2:
Input: [1, 2, 3, 5]
Output: false
Explanation: The array cannot be partitioned into equal sum subsets.
DP Accepted
這其實是一個01背包問題,對於每一個數,我們可以選擇放入和不放入,使dp[i][j]代表數組中前i個進行選擇能否可以累計得到j。dp[0][0]為1,其余情況dp[i][j] = dp[i-1][j] || dp[i-1][j-nums[i]],因為要麽不選擇,那麽就為dp[i-1][j],要麽選擇,那麽就為dp[i-1][j-nums[i]]。
class Solution { public: bool canPartition(vector<int>& nums) { int sum = accumulate(nums.begin(), nums.end(), 0); if (sum & 1) return false; int target = sum >> 1; vector<int> dp(target + 1, 0); dp[0] = 1; for (auto num : nums) for (int i = target; i >= num; i--) dp[i] = dp[i] || dp[i-num]; return dp[target]; } };
LN : leetcode 416 Partition Equal Subset Sum