## Algorithm

Problem Name: 956. Tallest Billboard

You are installing a billboard and want it to have the largest height. The billboard will have two steel supports, one on each side. Each steel support must be an equal height.

You are given a collection of `rods` that can be welded together. For example, if you have rods of lengths `1`, `2`, and `3`, you can weld them together to make a support of length `6`.

Return the largest possible height of your billboard installation. If you cannot support the billboard, return `0`.

Example 1:

```Input: rods = [1,2,3,6]
Output: 6
Explanation: We have two disjoint subsets {1,2,3} and {6}, which have the same sum = 6.
```

Example 2:

```Input: rods = [1,2,3,4,5,6]
Output: 10
Explanation: We have two disjoint subsets {2,3,5} and {4,6}, which have the same sum = 10.
```

Example 3:

```Input: rods = [1,2]
Output: 0
Explanation: The billboard cannot be supported, so we return 0.
```

Constraints:

• `1 <= rods.length <= 20`
• `1 <= rods[i] <= 1000`
• `sum(rods[i]) <= 5000`

## Code Examples

### #1 Code Example with Javascript Programming

```Code - Javascript Programming```

``````
const tallestBillboard = function(rods) {
const dp = {0 : 0}
for(let el of rods) {
for(let [diff, y] of Object.entries(dp)) {
diff = +diff
dp[diff + el] = Math.max(dp[diff + el] || 0, y)
if(diff >= el) dp[diff - el] = Math.max(dp[diff - el] || 0, y + el)
else dp[el - diff] = Math.max(dp[el - diff] || 0, y + diff)
}
}
return dp['0']
};
``````
Copy The Code &

Input

cmd
rods = [1,2,3,6]

Output

cmd
6

### #2 Code Example with Python Programming

```Code - Python Programming```

``````
class Solution:
def tallestBillboard(self, rods):
dp = {0: 0}
for x in rods:
for d, h in list(dp.items()):
dp[d + x] = max(dp.get(x + d, 0), h)
dp[abs(d - x)] = max(dp.get(abs(d - x), 0), h + min(d, x))
return dp[0]
``````
Copy The Code &

Input

cmd
rods = [1,2,3,6]

Output

cmd
6