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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3. //#include "algo/debug.h"
  4.  
  5. int N;
  6.  
  7.  
  8.  
  9. void gj(vector<vector<double>> A) {
  10.     // Gauss-Jordan Elimination
  11.     for (int k = 0; k < N; k++) {
  12.         // Partial Pivoting
  13.         int maxRow = k;
  14.         for (int i = k + 1; i < N; i++) {
  15.             if (abs(A[i][k]) > abs(A[maxRow][k])) {
  16.                 maxRow = i;
  17.             }
  18.         }
  19.         if (maxRow != k) {
  20.             swap(A[k], A[maxRow]);
  21.         }
  22.  
  23.         // Make diagonal element 1
  24.         double diag = A[k][k];
  25.         for (int j = 0; j <= N; j++) {
  26.             A[k][j] /= diag;
  27.         }
  28.  
  29.         // Make other elements in column 0
  30.         for (int i = 0; i < N; i++) {
  31.             if (i != k) {
  32.                 double r = A[i][k];
  33.                 for (int j = 0; j <= N; j++) {
  34.                     A[i][j] -= r * A[k][j];
  35.                 }
  36.             }
  37.         }
  38.     }
  39.  
  40.     // Display solutions
  41.     cout << "Solution:\n";
  42.     for (int i = 0; i < N; i++) {
  43.         cout << "x" << i+1 << ": " << A[i][N] << endl;
  44.     }
  45. }
  46.  
  47. signed main() {
  48.     //freopen("Error.txt", "w", stderr);
  49.     cout << "Enter N: \n";
  50.     cin >> N;
  51.     vector<vector<double>> A(N, vector<double>(N+1, 0));
  52.  
  53.     cout << "Enter: \n";
  54.     for (int i = 0; i<N; i++) {
  55.         for (int j = 0; j <= N; j++) {
  56.             cin >> A[i][j];
  57.         }
  58.     }
  59.     cout << "\nGauss-Jordan Elimination:\n";
  60.     gj(A);
  61.     return 0;
  62. }
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin
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3
5 10 1 28
1 1 1 6
4 8 3 29
stdout
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Enter N: 
Enter: 

Gauss-Jordan Elimination:
Solution:
x1: 1
x2: 2
x3: 3
https://ideone.com/V3M07Z
Gauss Jordan
language:
C++14 (gcc 8.3)
created:
8 days ago
visibility:
public

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