77 lines
2.1 KiB
C
77 lines
2.1 KiB
C
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// More of a math problem
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#include <stdio.h>
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#define MAX 100
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// *** THERE IS AN SIMPLER SOLUTION, THIS ONE IS BLOATED AND BAD ***
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//
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// There are two main movements:
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// 1: diagonal move, which includes two ways: i++&&j-- and i--&&j++
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// ^way = 0 ^way = 1
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// and for the diagonal move, the are six scenarios where the next step hits the
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// boundary.
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// a: nexti < n, nextj < 0 where i is valid. Results in i++
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// b: nexti < 0, nextj < n where j is valid. Results in j++
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// c: nexti >=n, nextj < 0 where none is valid. Results in j++
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// d: nexti <0, nextj >= n where none is valid. Results in i++
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// e: nexti >=n, nextj >=0 where j is valid. Results in j++
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// f: nexti >=0, nextj >=n where i is valid. Results in i++
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//
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// 2: horizontal and vertical move, which includes two ways as well: i++ and j++
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// The movement stops when i == j and j == n
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void fill(int matrix[][MAX], int n);
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int main(void) {
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int n;
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scanf("%d", &n);
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int matrix[n][MAX];
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fill(matrix, n);
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < n - 1; j++) {
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printf("%d ", matrix[i][j]);
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}
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printf("%d\n", matrix[i][n - 1]);
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}
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return 0;
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}
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void fill(int matrix[][MAX], int n) {
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int i = 0, j = 0;
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int nexti, nextj;
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int way = 1;
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int count = 1;
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while (count <= n * n) {
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matrix[i][j] = count++;
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if (way == 1) {
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nexti = i + 1;
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nextj = j - 1;
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} else {
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nexti = i - 1;
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nextj = j + 1;
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}
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// Validate if the next step is in the matrix.
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// First: the next step is within matrix.
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if (nexti >= 0 && nexti < n && nextj >= 0 && nextj < n) {
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i = nexti;
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j = nextj;
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} else {
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// Second: the next step is out of boundary.
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if (nextj < 0 && nexti < n) {
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i++;
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} else if (nexti < 0 && nextj < n) {
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j++;
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} else if (nexti >= n && nextj < 0) {
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j++;
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} else if (nexti < 0 && nextj >= n) {
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i++;
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} else if (nexti >= n && nextj >= 0) {
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j++;
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} else if (nexti >= 0 && nextj >= n) {
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i++;
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}
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way *= -1;
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}
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}
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}
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