Add 2nd homework

semester3/exercises/homework2.c

@@ -0,0 +1,131 @@
+#include <stdio.h>
+
+int MSS1(const int A[], int N) {
+  int thisSum, maxSum, i, j, k;
+
+  maxSum = 0;
+  int counter = 1;
+
+  printf("Algo 1\n");
+
+  for (i = 0; i < N; i++) {
+    for (j = i; j < N; j++) {
+      printf("%d run: (%d, %d)\n", counter++, thisSum, maxSum);
+      thisSum = 0;
+      for (k = i; k <= j; k++) {
+        thisSum += A[k];
+      }
+
+      if (thisSum > maxSum) {
+        maxSum = thisSum;
+      }
+    }
+  }
+
+  return maxSum;
+}
+
+int MSS2(const int A[], int N) {
+  int thisSum, maxSum, i, j;
+
+  maxSum = 0;
+  int counter = 1;
+
+  printf("Algo 2\n");
+
+  for (i = 0; i < N; i++) {
+    thisSum = 0;
+    for (j = i; j < N; j++) {
+      printf("%d run: (%d, %d)\n", counter++, thisSum, maxSum);
+      thisSum += A[j];
+
+      if (thisSum > maxSum) {
+        maxSum = thisSum;
+      }
+    }
+  }
+
+  return maxSum;
+}
+
+int Max3(int i, int j, int k) {
+  int max = i;
+  if (j > max) {
+    max = j;
+  }
+
+  if (k > max) {
+    max = k;
+  }
+
+  return max;
+}
+
+static int MaxSubSum(const int A[], int Left, int Right) {
+  int MaxLeftSum, MaxRightSum;
+  int MaxLeftBorderSum, MaxRightBorderSum;
+
+  int LeftBorderSum, RightBorderSum;
+
+  int Center, i;
+
+  if (Left == Right) /* Base Case */
+    if (A[Left] > 0)
+      return A[Left];
+    else
+      return 0;
+
+  Center = (Left + Right) / 2;
+  MaxLeftSum = MaxSubSum(A, Left, Center);
+  MaxRightSum = MaxSubSum(A, Center + 1, Right);
+
+  MaxLeftBorderSum = 0;
+  LeftBorderSum = 0;
+
+  for (i = Center; i >= Left; i--)
+    LeftBorderSum += A[i];
+  if (LeftBorderSum > MaxLeftBorderSum)
+    MaxLeftBorderSum = LeftBorderSum;
+
+  MaxRightBorderSum = 0;
+  RightBorderSum = 0;
+  for (i = Center + 1; i <= Right; i++)
+
+  {
+    RightBorderSum += A[i];
+    if (RightBorderSum > MaxRightBorderSum)
+      MaxRightBorderSum = RightBorderSum;
+  }
+  printf("MLS: %d, MRS: %d, MLBS: %d, MRBS: %d\n", MaxLeftSum, MaxRightSum,
+         MaxLeftBorderSum, MaxRightBorderSum);
+  return Max3(MaxLeftSum, MaxRightSum, MaxLeftBorderSum + MaxRightBorderSum);
+}
+
+int MSS4(const int A[], int N) {
+  int thisSum, maxSum, j;
+
+  thisSum = maxSum = 0;
+    int counter = 1;
+
+  for (j = 0; j < N; j++) {
+    printf("%d run: (%d, %d) \n", counter++, thisSum, maxSum);
+    thisSum += A[j];
+
+    if (thisSum > maxSum) {
+      maxSum = thisSum;
+    } else if (thisSum < 0) {
+      thisSum = 0;
+    }
+  }
+
+  return maxSum;
+}
+
+int main(void) {
+  const int input[] = {4, -3, 5, -2, -1, 2, 6, -2};
+  const int N = 8;
+
+  // printf("Answer: %d", MaxSubSum(input, 0, N - 1));
+  printf("Answer: %d", MSS4(input, N));
+  return 0;
+}