Am i the first one to finish these psets? IDK.

pset11/2-6-SneakyMatrix.c

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