LeetCode-in-All
416. Partition Equal Subset Sum
Medium
Given a non-empty array nums 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.
Example 1:
Input: nums = [1,5,11,5]
Output: true
Explanation: The array can be partitioned as [1, 5, 5] and [11].
Example 2:
Input: nums = [1,2,3,5]
Output: false
Explanation: The array cannot be partitioned into equal sum subsets.
Constraints:
1 <= nums.length <= 2001 <= nums[i] <= 100
Solution
class Solution {
/**
* @param Integer[] $nums
* @return Boolean
*/
public function canPartition($nums) {
$sums = 0;
foreach ($nums as $num) {
$sums += $num;
}
if ($sums % 2 == 1) {
return false;
}
$sums /= 2;
$dp = array_fill(0, $sums + 1, false);
$dp[0] = true;
foreach ($nums as $num) {
for ($sum = $sums; $sum >= $num; $sum--) {
$dp[$sum] = $dp[$sum] || $dp[$sum - $num];
}
}
return $dp[$sums];
}
}