移除除权重最小的边之外的所有出边
给定一个有 n 个节点的有向图。对于每个节点，删除除权重最小的出边之外的所有出边。对每个节点应用这个删除操作，然后打印最终的图形，其中图形的每个节点最多有一个输出边，并且具有最小权重。
注意：这里，为了方便，图被存储为邻接矩阵。
例子：
Input : Adjacency Matrix of input graph :
| 1 2 3 4
---------------
1 | 0 3 2 5
2 | 0 2 4 7
3 | 1 2 0 3
4 | 5 2 1 3
Output : Adjacency Matrix of output graph :
| 1 2 3 4
---------------
1 | 0 0 2 0
2 | 0 2 0 0
3 | 1 0 0 0
4 | 0 0 1 0对于图的邻接矩阵的每一行，保持最小元素（零除外），其余全部为零。对输入矩阵的每一行执行此操作。最后，打印结果矩阵。
例子 ：
C++
// CPP program for minimizing graph
#include
using namespace std;
// Utility function for
// finding min of a row
int minFn(int arr[])
{
int min = INT_MAX;
for (int i = 0; i < 4; i++)
if (min > arr[i])
min = arr[i];
return min;
}
// Utility function for minimizing graph
void minimizeGraph(int arr[][4])
{
int min;
// Set empty edges to INT_MAX
for (int i = 0; i < 4; i++)
for (int j = 0; j < 4; j++)
if (arr[i][j] == 0)
arr[i][j] = INT_MAX;
// Finding minimum of each row
// and deleting rest of edges
for (int i = 0; i < 4; i++) {
// Find minimum element of row
min = minFn(arr[i]);
for (int j = 0; j < 4; j++) {
// If edge value is not min
// set it to zero, also
// edge value INT_MAX denotes that
// initially edge value was zero
if (!(arr[i][j] == min) || (arr[i][j] == INT_MAX))
arr[i][j] = 0;
else
min = 0;
}
}
// Print result;
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++)
cout << arr[i][j] << " ";
cout << "\n";
}
}
// Driver Program
int main()
{
// Input Graph
int arr[4][4] = { 1, 2, 4, 0,
0, 0, 0, 5,
0, 2, 0, 3,
0, 0, 0, 0 };
minimizeGraph(arr);
return 0;
} Java
// Java program for
// minimizing graph
import java.io.*;
import java.util.*;
import java.lang.*;
class GFG {
// Utility function for
// finding min of a row
static int minFn(int arr[])
{
int min = Integer.MAX_VALUE;
for (int i = 0;
i < arr.length; i++)
if (min > arr[i])
min = arr[i];
return min;
}
// Utility function
// for minimizing graph
static void minimizeGraph(int arr[][])
{
int min;
// Set empty edges
// to INT_MAX
for (int i = 0;
i < arr.length; i++)
for (int j = 0;
j < arr.length; j++)
if (arr[i][j] == 0)
arr[i][j] = Integer.MAX_VALUE;
// Finding minimum of each
// row and deleting rest
// of edges
for (int i = 0;
i < arr.length; i++) {
// Find minimum
// element of row
min = minFn(arr[i]);
for (int j = 0;
j < arr.length; j++) {
// If edge value is not
// min set it to zero,
// also edge value INT_MAX
// denotes that initially
// edge value was zero
if ((arr[i][j] != min) || (arr[i][j] == Integer.MAX_VALUE))
arr[i][j] = 0;
else
min = 0;
}
}
// Print result;
for (int i = 0;
i < arr.length; i++) {
for (int j = 0;
j < arr.length; j++)
System.out.print(arr[i][j] + " ");
System.out.print("\n");
}
}
// Driver Code
public static void main(String[] args)
{
// Input Graph
int arr[][] = { { 1, 2, 4, 0 },
{ 0, 0, 0, 5 },
{ 0, 2, 0, 3 },
{ 0, 0, 0, 0 } };
minimizeGraph(arr);
}
}Python3
# Python3 program for minimizing graph
# Utility function for finding min of a row
def minFn(arr):
minimum = float('inf')
for i in range(0, 4):
if minimum > arr[i]:
minimum = arr[i]
return minimum
# Utility function for minimizing graph
def minimizeGraph(arr):
# Set empty edges to INT_MAX
for i in range(0, 4):
for j in range(0, 4):
if arr[i][j] == 0:
arr[i][j] = float('inf')
# Finding minimum of each row
# and deleting rest of edges
for i in range(0, 4):
# Find minimum element of row
minimum = minFn(arr[i])
for j in range(0, 4):
# If edge value is not min
# set it to zero, also
# edge value INT_MAX denotes that
# initially edge value was zero
if ((not(arr[i][j] == minimum)) or
(arr[i][j] == float('inf'))):
arr[i][j] = 0
else:
minimum = 0
# Print result
for i in range(0, 4):
for j in range(0, 4):
print(arr[i][j], end = " ")
print()
# Driver Code
if __name__ == "__main__":
# Input Graph
arr = [[1, 2, 4, 0],
[0, 0, 0, 5],
[0, 2, 0, 3],
[0, 0, 0, 0]]
minimizeGraph(arr)
# This code is contributed by
# Rituraj JainC#
// C# program for
// minimizing graph
using System;
class GFG {
// Utility function for
// finding min of a row
static int minFn(int[] arr)
{
int min = int.MaxValue;
for (int i = 0;
i < arr.Length; i++)
if (min > arr[i])
min = arr[i];
return min;
}
// Utility function
// for minimizing graph
static void minimizeGraph(int[, ] arr)
{
int min;
// Set empty edges
// to INT_MAX
for (int i = 0;
i < arr.GetLength(0); i++)
for (int j = 0;
j < arr.GetLength(1); j++)
if (arr[i, j] == 0)
arr[i, j] = int.MaxValue;
// Finding minimum of each
// row and deleting rest
// of edges
for (int i = 0; i < arr.GetLength(0); i++) {
// Find minimum
// element of row
min = minFn(GetRow(arr, i));
for (int j = 0;
j < arr.GetLength(1); j++) {
// If edge value is not
// min set it to zero,
// also edge value INT_MAX
// denotes that initially
// edge value was zero
if ((arr[i, j] != min) || (arr[i, j] == int.MaxValue))
arr[i, j] = 0;
else
min = 0;
}
}
// Print result;
for (int i = 0;
i < arr.GetLength(0); i++) {
for (int j = 0;
j < arr.GetLength(1); j++)
Console.Write(arr[i, j] + " ");
Console.Write("\n");
}
}
public static int[] GetRow(int[, ] matrix, int row)
{
var rowLength = matrix.GetLength(1);
var rowVector = new int[rowLength];
for (var i = 0; i < rowLength; i++)
rowVector[i] = matrix[row, i];
return rowVector;
}
// Driver Code
public static void Main(String[] args)
{
// Input Graph
int[, ] arr = { { 1, 2, 4, 0 },
{ 0, 0, 0, 5 },
{ 0, 2, 0, 3 },
{ 0, 0, 0, 0 } };
minimizeGraph(arr);
}
}
// This code contributed by Rajput-JiPHP
$arr[$i])
$min = $arr[$i];
return $min;
}
// Utility function for minimizing graph
function minimizeGraph($arr)
{
$min;
// Set empty edges to INT_MAX
for ($i = 0; $i < 4; $i++)
for ($j = 0; $j < 4; $j++)
if ($arr[$i][$j] == 0)
$arr[$i][$j] = PHP_INT_MAX;
// Finding minimum of each row
// and deleting rest of edges
for ($i = 0; $i < 4; $i++)
{
// Find minimum element of row
$min = minFn($arr[$i]);
for ($j = 0; $j < 4; $j++)
{
// If edge value is not min
// set it to zero, also
// edge value INT_MAX denotes that
// initially edge value was zero
if (!($arr[$i][$j] == $min) ||
($arr[$i][$j] == PHP_INT_MAX))
$arr[$i][$j] = 0;
else
$min = 0;
}
}
// Print result;
for ($i = 0; $i < 4; $i++)
{
for ($j = 0; $j < 4; $j++)
echo $arr[$i][$j], " ";
echo "\n";
}
}
// Driver Code
// Input Graph
$arr = array(array(1, 2, 4, 0),
array(0, 0, 0, 5),
array(0, 2, 0, 3),
array(0, 0, 0, 0));
minimizeGraph($arr);
// This code is contributed by ajit.
?>Javascript
输出：
1 0 0 0
0 0 0 5
0 2 0 0
0 0 0 0时间复杂度：O(n^2)
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