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2035.Partition Array Into Two Arrays to Minimize Sum Difference

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English Version

题目描述

给你一个长度为 2 * n 的整数数组。你需要将 nums 分成 两个 长度为 n 的数组,分别求出两个数组的和,并 最小化 两个数组和之 差的绝对值 。nums 中每个元素都需要放入两个数组之一。

请你返回 最小 的数组和之差。

 

示例 1:

example-1

输入:nums = [3,9,7,3]
输出:2
解释:最优分组方案是分成 [3,9] 和 [7,3] 。
数组和之差的绝对值为 abs((3 + 9) - (7 + 3)) = 2 。

示例 2:

输入:nums = [-36,36]
输出:72
解释:最优分组方案是分成 [-36] 和 [36] 。
数组和之差的绝对值为 abs((-36) - (36)) = 72 。

示例 3:

example-3

输入:nums = [2,-1,0,4,-2,-9]
输出:0
解释:最优分组方案是分成 [2,4,-9] 和 [-1,0,-2] 。
数组和之差的绝对值为 abs((2 + 4 + -9) - (-1 + 0 + -2)) = 0 。

 

提示:

  • 1 <= n <= 15
  • nums.length == 2 * n
  • -107 <= nums[i] <= 107

解法

Python3

class Solution:
    def minimumDifference(self, nums: List[int]) -> int:
        n = len(nums) >> 1
        f = defaultdict(set)
        g = defaultdict(set)
        for i in range(1 << n):
            s = cnt = 0
            s1 = cnt1 = 0
            for j in range(n):
                if (i & (1 << j)) != 0:
                    s += nums[j]
                    cnt += 1
                    s1 += nums[n + j]
                    cnt1 += 1
                else:
                    s -= nums[j]
                    s1 -= nums[n + j]
            f[cnt].add(s)
            g[cnt1].add(s1)

        ans = float('inf')
        for i in range(n + 1):
            fi, gi = sorted(list(f[i])), sorted(list(g[n - i]))
            # min(abs(f[i] + g[n - i]))
            for a in fi:
                left, right = 0, len(gi) - 1
                b = -a
                while left < right:
                    mid = (left + right) >> 1
                    if gi[mid] >= b:
                        right = mid
                    else:
                        left = mid + 1
                ans = min(ans, abs(a + gi[left]))
                if left > 0:
                    ans = min(ans, abs(a + gi[left - 1]))
        return ans

Java

class Solution {
    public int minimumDifference(int[] nums) {
        int n = nums.length >> 1;
        Map<Integer, Set<Integer>> f = new HashMap<>();
        Map<Integer, Set<Integer>> g = new HashMap<>();
        for (int i = 0; i < (1 << n); ++i) {
            int s = 0, cnt = 0;
            int s1 = 0, cnt1 = 0;
            for (int j = 0; j < n; ++j) {
                if ((i & (1 << j)) != 0) {
                    s += nums[j];
                    ++cnt;
                    s1 += nums[n + j];
                    ++cnt1;
                } else {
                    s -= nums[j];
                    s1 -= nums[n + j];
                }
            }
            f.computeIfAbsent(cnt, k -> new HashSet<>()).add(s);
            g.computeIfAbsent(cnt1, k -> new HashSet<>()).add(s1);
        }
        int ans = Integer.MAX_VALUE;
        for (int i = 0; i <= n; ++i) {
            List<Integer> fi = new ArrayList<>(f.get(i));
            List<Integer> gi = new ArrayList<>(g.get(n - i));
            Collections.sort(fi);
            Collections.sort(gi);
            for (int a : fi) {
                int left = 0, right = gi.size() - 1;
                int b = -a;
                while (left < right) {
                    int mid = (left + right) >> 1;
                    if (gi.get(mid) >= b) {
                        right = mid;
                    } else {
                        left = mid + 1;
                    }
                }
                ans = Math.min(ans, Math.abs(a + gi.get(left)));
                if (left > 0) {
                    ans = Math.min(ans, Math.abs(a + gi.get(left - 1)));
                }
            }
        }
        return ans;
    }
}

C++

class Solution {
public:
    int minimumDifference(vector<int>& nums) {
        int n = nums.size() >> 1;
        vector<vector<int>> f(n + 1), g(n + 1);
        for (int i = 0; i < (1 << n); ++i)
        {
            int s = 0, cnt = 0;
            int s1 = 0, cnt1 = 0;
            for (int j = 0; j < n; ++j)
            {
                if (i & (1 << j))
                {
                    s += nums[j];
                    ++cnt;
                    s1 += nums[n + j];
                    ++cnt1;
                }
                else
                {
                    s -= nums[j];
                    s1 -= nums[n + j];
                }
            }
            f[cnt].push_back(s);
            g[cnt1].push_back(s1);
        }
        for (int i = 0; i <= n; ++i)
        {
            sort(f[i].begin(), f[i].end());
            sort(g[i].begin(), g[i].end());
        }
        int ans = INT_MAX;
        for (int i = 0; i <= n; ++i)
        {
            for (int a : f[i])
            {
                int left = 0, right = g[n - i].size() - 1;
                int b = -a;
                while (left < right)
                {
                    int mid = (left + right) >> 1;
                    if (g[n - i][mid] >= b) right = mid;
                    else left = mid + 1;
                }
                ans = min(ans, abs(a + g[n - i][left]));
                if (left > 0) ans = min(ans, abs(a + g[n - i][left - 1]));
            }
        }
        return ans;
    }
};

Go

func minimumDifference(nums []int) int {
	n := len(nums) >> 1
	f := make([][]int, n+1)
	g := make([][]int, n+1)
	for i := 0; i < (1 << n); i++ {
		s, cnt := 0, 0
		s1, cnt1 := 0, 0
		for j := 0; j < n; j++ {
			if (i & (1 << j)) != 0 {
				s += nums[j]
				cnt++
				s1 += nums[n+j]
				cnt1++
			} else {
				s -= nums[j]
				s1 -= nums[n+j]
			}
		}
		f[cnt] = append(f[cnt], s)
		g[cnt1] = append(g[cnt1], s1)
	}

	for i := 0; i <= n; i++ {
		sort.Ints(f[i])
		sort.Ints(g[i])
	}
	ans := 1 << 30
	for i := 0; i <= n; i++ {
		for _, a := range f[i] {
			left, right := 0, len(g[n-i])-1
			b := -a
			for left < right {
				mid := (left + right) >> 1
				if g[n-i][mid] >= b {
					right = mid
				} else {
					left = mid + 1
				}
			}
			ans = min(ans, abs(a+g[n-i][left]))
			if left > 0 {
				ans = min(ans, abs(a+g[n-i][left-1]))
			}
		}
	}
	return ans
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

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