Coupon

AtCoder
IDabc246_c
Time2000ms
Memory256MB
Difficulty
There are $N$ items in a shop. For each $i = 1, 2, \ldots, N$, the price of the $i$\-th item is $A_i$ yen (the currency of Japan). Takahashi has $K$ coupons. Each coupon can be used on one item. You can use any number of coupons, possibly zero, on the same item. Using $k$ coupons on an item with a price of $a$ yen allows you to buy it for $\max\lbrace a - kX, 0\rbrace$ yen. Print the minimum amount of money Takahashi needs to buy all the items. ## Constraints * $1 \leq N \leq 2 \times 10^5$ * $1 \leq K, X \leq 10^9$ * $1 \leq A_i \leq 10^9$ * All values in input are integers. ## Input Input is given from Standard Input in the following format: $N$ $K$ $X$ $A_1$ $A_2$ $\ldots$ $A_N$ [samples]
Samples
Input #1
5 4 7
8 3 10 5 13
Output #1
12

By using $1$ coupon on the $1$\-st item, $1$ coupon on the $3$\-rd item, and $2$ coupons on the $5$\-th item, Takahashi can:

*   buy the $1$\-st item for $\max\lbrace A_1-X, 0 \rbrace = 1$ yen,
*   buy the $2$\-nd item for $\max\lbrace A_2, 0 \rbrace = 3$ yen,
*   buy the $3$\-rd item for $\max\lbrace A_3-X, 0 \rbrace = 3$ yen,
*   buy the $4$\-th item for $\max\lbrace A_4, 0 \rbrace = 5$ yen,
*   buy the $5$\-th item for $\max\lbrace A_5-2X, 0 \rbrace = 0$ yen,

for a total of $1 + 3 + 3 + 5 + 0 = 12$ yen, which is the minimum possible.
Input #2
5 100 7
8 3 10 5 13
Output #2
0
Input #3
20 815 60
2066 3193 2325 4030 3725 1669 1969 763 1653 159 5311 5341 4671 2374 4513 285 810 742 2981 202
Output #3
112
API Response (JSON)
{
  "problem": {
    "name": "Coupon",
    "description": {
      "content": "There are $N$ items in a shop. For each $i = 1, 2, \\ldots, N$, the price of the $i$\\-th item is $A_i$ yen (the currency of Japan). Takahashi has $K$ coupons.   Each coupon can be used on one item. You",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
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    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc246_c"
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  "statements": [
    {
      "statement_type": "Markdown",
      "content": "There are $N$ items in a shop. For each $i = 1, 2, \\ldots, N$, the price of the $i$\\-th item is $A_i$ yen (the currency of Japan).\nTakahashi has $K$ coupons.  \nEach coupon can be used on one item. You...",
      "is_translate": false,
      "language": "English"
    }
  ]
}
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