Trace Ones and Zeroes with strings ["10","0001","111001","1","0"], m=5 zeros, n=3 ones. Each string has a cost (zeros,ones): (1,1), (3,1), (2,4), (0,1), (1,0). DP is dp[i][j] = max strings with i zeros and j ones. Process strings like 0/1 Knapsack but with 2D capacity. Optimal: take "10" (1,1), "0001" (3,1), "1" (0,1) = total (4,3) which fits in (5,3).
Answer: 3 strings.