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:
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.
01背包问题,v = sum(nums[i])/2那么原问题可以转换为将n个物品装入容量为v的背包中能得到的最大值。如果最大值为v那么就返回true否则返回false
class Solution {
public:
bool canPartition(vector<int>& nums) {
int n = nums.size();
int v = accumulate(nums.begin(), nums.end(), 0);
if (v & 1) return false;
v /= 2;
vector<int> dp(v+1);
// dp[i][j] = max(dp[i-1][j],dp[i-1][j-a[i]] + w[i]);
for (int i = 0; i < n; ++i) {
for (int j = v; j >= nums[i]; --j) {
dp[j] = max(dp[j-nums[i]] + nums[i], dp[j]);
}
}
cout << dp[v] <<endl;
return (dp[v] == v);
}
};
原文地址:http://www.cnblogs.com/pk28/
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