City Savers

AtCoder

IDabc135_c

Time2000ms

Memory256MB

Difficulty—

There are $N+1$ towns. The $i$\-th town is being attacked by $A_i$ monsters. We have $N$ heroes. The $i$\-th hero can defeat monsters attacking the $i$\-th or $(i+1)$\-th town, for a total of at most $B_i$ monsters. What is the maximum total number of monsters the heroes can cooperate to defeat? ## Constraints * All values in input are integers. * $1 \leq N \leq 10^5$ * $1 \leq A_i \leq 10^9$ * $1 \leq B_i \leq 10^9$ ## Input Input is given from Standard Input in the following format: $N$ $A_1$ $A_2$ $...$ $A_{N+1}$ $B_1$ $B_2$ $...$ $B_N$ [samples]

Samples

Input #1

2
3 5 2
4 5

Output #1

9

If the heroes choose the monsters to defeat as follows, they can defeat nine monsters in total, which is the maximum result.

*   The first hero defeats two monsters attacking the first town and two monsters attacking the second town.
*   The second hero defeats three monsters attacking the second town and two monsters attacking the third town.

Input #2

3
5 6 3 8
5 100 8

Output #2

Input #3

2
100 1 1
1 100

Output #3

API Response (JSON)

{
  "problem": {
    "name": "City Savers",
    "description": {
      "content": "There are $N+1$ towns. The $i$\\-th town is being attacked by $A_i$ monsters. We have $N$ heroes. The $i$\\-th hero can defeat monsters attacking the $i$\\-th or $(i+1)$\\-th town, for a total of at most ",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc135_c"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "There are $N+1$ towns. The $i$\\-th town is being attacked by $A_i$ monsters.\nWe have $N$ heroes. The $i$\\-th hero can defeat monsters attacking the $i$\\-th or $(i+1)$\\-th town, for a total of at most ...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments