input: Write a python function to solve the 0-1 knapsack problem using dynamic programming.
  assert knapSack(10, [1, 2, 3, 8, 7, 4], [20, 5, 10, 40, 15, 25], 6) == 60
  assert knapSack(7, [5, 3, 4, 2], [60, 50, 70, 30], 4) == 80
  assert knapSack(50, [10, 20, 30], [60, 100, 120], 3) == 220
output: def knapSack(W, wt, val, n):
      K = [[0 for x in range(W + 1)] for x in range(n + 1)]
  
      for i in range(n + 1):
          for w in range(W + 1):
              if i == 0 or w == 0:
                  K[i][w] = 0
              elif wt[i - 1] <= w:
                  K[i][w] = max(val[i - 1] + K[i - 1][w - wt[i - 1]], K[i - 1][w])
              else:
                  K[i][w] = K[i - 1][w]
  
      return K[n][W]