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:

Example 2:

Approach #1: DP. [C++]

　　

Analysis:

dp[i][j] : whether we can sum to j using first i numbers.

dp[i][j] = true if dp[i-1][j-num]

check dp[n-1][sum/2]

init dp[-1][0] = true

Time complexity: O(n^2*sum) -> O(n*sum)

Space complexity: O(sum)

永远渴望，大智若愚（stay hungry, stay foolish）