测评会员优惠活动进行中 · 开通 VIP,有效期内测评不限次 VIP 优惠中 · 测评不限次 立即查看

A10603. Sea Battle

编程题 普及/提高-

题目描述

Galya is playing one-dimensional Sea Battle on a $1×n$ grid. In this game $a$ ships are placed on the grid. Each of the ships consists of $b$ consecutive cells. No cell can be part of two ships, however, the ships can touch each other.

Galya doesn't know the ships location. She can shoot to some cells and after each shot she is told if that cell was a part of some ship (this case is called "hit") or not (this case is called "miss").

Galya has already made $k$ shots, all of them were misses.

Your task is to calculate the minimum number of cells such that if Galya shoot at all of them, she would hit at least one ship.

It is guaranteed that there is at least one valid ships placement.

输入格式

The first line contains four positive integers $n$ , $a$ , $b$ , $k$ ( $1<=n<=2·10^{5}$ , $1<=a,b<=n$ , $0<=k<=n-1$ ) — the length of the grid, the number of ships on the grid, the length of each ship and the number of shots Galya has already made.

The second line contains a string of length $n$ , consisting of zeros and ones. If the $i$ -th character is one, Galya has already made a shot to this cell. Otherwise, she hasn't. It is guaranteed that there are exactly $k$ ones in this string.

输出格式

In the first line print the minimum number of cells such that if Galya shoot at all of them, she would hit at least one ship.

In the second line print the cells Galya should shoot at.

Each cell should be printed exactly once. You can print the cells in arbitrary order. The cells are numbered from $1$ to $n$ , starting from the left.

If there are multiple answers, you can print any of them.

输入输出样例

输入 #1
5 1 2 1
00100
输出 #1
2
4 2
输入 #2
13 3 2 3
1000000010001
输出 #2
2
7 11

说明/提示

There is one ship in the first sample. It can be either to the left or to the right from the shot Galya has already made (the "1" character). So, it is necessary to make two shots: one at the left part, and one at the right part.
上一题 去做题 下一题