All tasks are done!

2025.03.14/09Ex/solve.c

@@ -0,0 +1,32 @@
+#include "solve.h"
+#include <math.h>
+
+#define eps 1e-9
+
+int compare(const double a, const double b)
+{
+	if (a - b > eps) return 1;
+	else if (b - a > eps) return -1;
+	return 0;
+}
+
+double t9_solve(double *a, int n, int m)
+{
+	int i, j;
+	double cur = 0, maximum = 0;
+	for (i = 0; i < n; i++)
+		for (j = 0; j < m; j++)
+			if (i == 0 || i == n-1 || j == 0 || j == m-1)
+				if (compare(fabs(a[i*m + j]), maximum) == 1)
+					maximum = fabs(a[i*m + j]);
+	
+	for (i = 1; i < n-1; i++)
+		for (j = m-2; j > 0; j--)
+		{
+			cur = (a[(i-1)*m + j] + a[(i+1)*m + j] + a[i*m + (j-1)] + a[i*m + (j+1)]) / 5;
+			if (compare(fabs(cur), maximum) == 1) maximum = fabs(cur);
+			a[i*m + j] = cur;
+		}
+
+	return maximum;
+}