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📜  最大子集和,使得集合中没有两个元素具有相同的数字

📅  最后修改于: 2021-09-17 07:34:39             🧑  作者: Mango

给定一个包含 N 个元素的数组。找到具有最大和的元素子集,使得子集中没有两个元素具有公共数字。
例子:

  • 这里我们可以使用动态规划和位掩码来解决这个问题。
  • 考虑每个数字的 10 位表示,如果该数字中存在与该位对应的数字,则每个位为 1。
  • 现在维护一个 dp[i],它存储可以用集合中存在的所有数字实现的最大可能和,对应于 i 的二进制表示中为 1 的位位置。
  • 循环关系的形式为dp[i] = max(dp[i], dp[i^mask] + a[j]) ,对于从 1 到 n 的所有 j 使得掩码(a 的 10 位表示) [j]) 满足 i ||面具 = i。 (从那时起,只有我们可以确保满足 i 中的所有可用数字)。

下面是上述方法的实现:

C++
// C++ implementation of above approach
#include 
using namespace std;
int dp[1024];
  
// Function to create mask for every number
int get_binary(int u)
{
    int ans = 0;
    while (u) {
        int rem = u % 10;
        ans |= (1 << rem);
        u /= 10;
    }
  
    return ans;
}
  
// Recursion for Filling DP array
int recur(int u, int array[], int n)
{
    // Base Condition
    if (u == 0)
        return 0;
    if (dp[u] != -1)
        return dp[u];
  
    int temp = 0;
    for (int i = 0; i < n; i++) {
        int mask = get_binary(array[i]);
  
        // Recurrence Relation
        if ((mask | u) == u) {
            dp[u] = max(max(0,
                    dp[u ^ mask]) + array[i], dp[u]);
        }
    }
  
    return dp[u];
}
  
// Function to find Maximum Subset Sum
int solve(int array[], int n)
{
    // Initialize DP array
    for (int i = 0; i < (1 << 10); i++) {
        dp[i] = -1;
    }
  
    int ans = 0;
  
    // Iterate over all possible masks of 10 bit number
    for (int i = 0; i < (1 << 10); i++) {
        ans = max(ans, recur(i, array, n));
    }
  
    return ans;
}
  
// Driver Code
int main()
{
    int array[] = { 22, 132, 4, 45, 12, 223 };
    int n = sizeof(array) / sizeof(array[0]);
     
    cout << solve(array, n);
}


Java
// Java implementation of above approach
import java.io.*;
 
class GFG
{
     
static int []dp = new int [1024];
 
// Function to create mask for every number
static int get_binary(int u)
{
    int ans = 0;
    while (u > 0)
     
    {
        int rem = u % 10;
        ans |= (1 << rem);
        u /= 10;
    }
 
    return ans;
}
 
// Recursion for Filling DP array
static int recur(int u, int []array, int n)
{
    // Base Condition
    if (u == 0)
        return 0;
    if (dp[u] != -1)
        return dp[u];
 
    for (int i = 0; i < n; i++)
    {
        int mask = get_binary(array[i]);
 
        // Recurrence Relation
        if ((mask | u) == u)
        {
            dp[u] = Math.max(Math.max(0,
                    dp[u ^ mask]) + array[i], dp[u]);
        }
    }
 
    return dp[u];
}
 
// Function to find Maximum Subset Sum
static int solve(int []array, int n)
{
    // Initialize DP array
    for (int i = 0; i < (1 << 10); i++)
    {
        dp[i] = -1;
    }
 
    int ans = 0;
 
    // Iterate over all possible masks of 10 bit number
    for (int i = 0; i < (1 << 10); i++)
    {
        ans = Math.max(ans, recur(i, array, n));
    }
 
    return ans;
}
 
// Driver Code
static public void main (String[] args)
{
    int []array = { 22, 132, 4, 45, 12, 223 };
    int n = array.length;
     
    System.out.println(solve(array, n));
}
}
 
// This code is contributed by anuj_67..


Python3
# Python3 implementation of above approach
 
dp = [0]*1024;
 
# Function to create mask for every number
def get_binary(u) :
 
    ans = 0;
    while (u) :
        rem = u % 10;
        ans |= (1 << rem);
        u //= 10;
    return ans;
 
 
# Recursion for Filling DP array
def recur(u, array, n) :
 
    # Base Condition
    if (u == 0) :
        return 0;
         
    if (dp[u] != -1) :
        return dp[u];
 
    temp = 0;
    for i in range(n) :
        mask = get_binary(array[i]);
 
        # Recurrence Relation
        if ((mask | u) == u) :
            dp[u] = max(max(0, dp[u ^ mask]) + array[i], dp[u]);
 
    return dp[u];
 
 
# Function to find Maximum Subset Sum
def solve(array, n)  :
    i = 0
     
    # Initialize DP array
    while(i < (1 << 10)) :
        dp[i] = -1;
        i += 1
     
    ans = 0;
 
    i = 0
    # Iterate over all possible masks of 10 bit number
    while(i < (1 << 10)) :
        ans = max(ans, recur(i, array, n));
         
        i += 1
     
    return ans;
 
# Driver Code
if __name__ ==  "__main__" :
 
    array = [ 22, 132, 4, 45, 12, 223 ] ;
    n = len(array);
     
    print(solve(array, n));
     
    # This code is contributed by AnkitRai01


C#
// C# implementation of above approach
using System;
 
class GFG
{
     
static int []dp = new int [1024];
 
// Function to create mask for every number
static int get_binary(int u)
{
    int ans = 0;
    while (u > 0)
     
    {
        int rem = u % 10;
        ans |= (1 << rem);
        u /= 10;
    }
 
    return ans;
}
 
// Recursion for Filling DP array
static int recur(int u, int []array, int n)
{
    // Base Condition
    if (u == 0)
        return 0;
    if (dp[u] != -1)
        return dp[u];
 
    for (int i = 0; i < n; i++)
    {
        int mask = get_binary(array[i]);
 
        // Recurrence Relation
        if ((mask | u) == u)
        {
            dp[u] = Math.Max(Math.Max(0,
                    dp[u ^ mask]) + array[i], dp[u]);
        }
    }
 
    return dp[u];
}
 
// Function to find Maximum Subset Sum
static int solve(int []array, int n)
{
    // Initialize DP array
    for (int i = 0; i < (1 << 10); i++)
    {
        dp[i] = -1;
    }
 
    int ans = 0;
 
    // Iterate over all possible masks of 10 bit number
    for (int i = 0; i < (1 << 10); i++)
    {
        ans = Math.Max(ans, recur(i, array, n));
    }
 
    return ans;
}
 
// Driver Code
static public void Main ()
{
    int []array = { 22, 132, 4, 45, 12, 223 };
    int n = array.Length;
     
    Console.WriteLine (solve(array, n));
}
}
 
// This code is contributed by ajit.


Javascript


输出:

268

时间复杂度: O(N*(2^10))

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