8, 9, 10 tasks are done

2025.03.21/10Ex/solve.c

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+#include "solve.h"
+#include <math.h>
+#include <float.h>
+#include <stdio.h>
+
+int t10_solve(double *a, int m, int n)
+{
+	int min_i = 0, min_j = 0;
+	double minimum = DBL_MAX;
+	double inn = 1./n, inm = 1./m;
+
+	for (int i = 0; i < m; i++)
+	{
+		double cur = 0;
+		double sum = 0;
+		double sq_sum = 0;
+		for (int j = 0; j < n; j++)
+		{	
+			double temp = a[i*n + j];
+			sum += temp;
+			sq_sum += temp * temp;
+		}
+
+		cur = sq_sum - (sum * sum) * inn;
+		if ((minimum - cur) > DBL_EPSILON * fmax(fabs(minimum), fabs(cur))) {
+			minimum = cur;
+			min_i = i;
+		}
+	}
+
+	minimum = DBL_MAX;
+	for (int j = 0; j < n; j++)
+	{
+		const int BS = 32;
+		double cur = 0;
+		double sum = 0;
+		double sq_sum = 0;
+
+		for (int ii = 0; ii < m; ii += BS)
+			for (int i = ii; i < ii + BS && i < m; i++)
+			{
+				double temp = a[i*n + j];
+				sum += temp;
+				sq_sum += temp * temp;
+			}
+
+		cur = sq_sum - (sum * sum) * inm;
+		if ((minimum - cur) > DBL_EPSILON * fmax(fabs(minimum), fabs(cur))) {
+			minimum = cur;
+			min_j = j;
+		}
+	}
+	
+	for (int l = min_j+1, del_j = 1; l < min_i*n; l++)
+	{
+		if (l == ((n * del_j) + min_j))
+			del_j++;
+		else 
+			a[l - del_j] = a[l];
+	}
+
+	for (int l = (min_i+1)*n, del_j = min_i; l < m*n; l++)
+	{
+		if (l == ((n * (del_j + 1)) + min_j))
+			del_j++;
+		else 
+			a[l - del_j - n] = a[l];
+	}
+
+	return min_i * n + min_j;
+}