From 77abcfee85411463d7df724a54daef5d8d153113 Mon Sep 17 00:00:00 2001
From: Valentin Gehrke <madmaurice@zom.bi>
Date: Mon, 15 Feb 2016 10:14:58 +0100
Subject: [PATCH] Gauss algorithmus part 1

---
 gauss.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 gauss.c

diff --git a/gauss.c b/gauss.c
new file mode 100644
index 0000000..ff8adc6
--- /dev/null
+++ b/gauss.c
@@ -0,0 +1,82 @@
+#include <stdio.h>
+#include <assert.h>
+#include <stdlib.h>
+
+typedef struct {
+    int ** data;
+    int size;
+} Matrix;
+
+Matrix matCreate(int size) {
+    int** data = malloc(sizeof(int*) * size);
+    for(unsigned int row = 0; row < size; row++) data[row] = malloc(sizeof(int)*size);
+    return (Matrix){data,size};
+}
+
+void matSet(Matrix m, size_t row, size_t col, int v) {
+    assert(row < m.size);
+    assert(col < m.size);
+    m.data[row][col] = v;
+}
+
+int matGet(Matrix m, size_t row, size_t col) {
+    assert(row < m.size);
+    assert(col < m.size);
+    return m.data[row][col];
+}
+
+void matSwapRows(Matrix m, size_t row1, size_t row2) {
+    assert(row1 < m.size);
+    assert(row2 < m.size);
+    int* tmp = m.data[row1];
+    m.data[row1] = m.data[row2];
+    m.data[row2] = tmp;
+}
+
+void matPrint(Matrix m) {
+    for(unsigned int row = 0; row < m.size; row++) {
+        for(unsigned int col = 0; col < m.size; col++) {
+            printf("%02d ", matGet(m,row,col));
+        }
+        printf("\n");
+    }
+}
+
+void matFree(Matrix m) {
+    for(unsigned int row = 0; row < m.size; row++) free(m.data[row]);
+    free(m.data);
+}
+
+int reorder_mat(Matrix m, int rowCol) {
+    if(rowCol >= m.size) return 1;
+    if(matGet(m,rowCol,rowCol) != 0) return reorder_mat(m,rowCol+1);
+
+    for(int candidate = rowCol+1; candidate < m.size; candidate++) {
+        if(matGet(m,candidate, rowCol) != 0) {
+            matSwapRows(m, rowCol, candidate);
+            if(reorder_mat(m, rowCol+1)) return 1;
+            matSwapRows(m, rowCol, candidate);
+        }
+    }
+
+    return 0;
+}
+
+int main( int argc, char *argv[] ) {
+
+    Matrix m = matCreate(2);
+    matSet(m,0,0,0);
+    matSet(m,0,1,1);
+    matSet(m,1,0,1);
+    matSet(m,1,1,0);
+
+    matPrint(m);
+
+    if(!reorder_mat(m,0)) {
+        printf("Failed\n");
+    }
+
+    matPrint(m);
+
+	return 0;
+}