Kamen

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("arch=sandybridge")
#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define F first
#define S second
using pi=pair<int,int>;
using ii=long long;
#define N 30100
#define M 35
set<int> asd[M];
char board[N][M];
int n, m;
inline int isfree(int y, int x)
{
    if (y >= n || x >= m || y < 0 || x < 0) return 0;
    return board[y][x] == '.';
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> m;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            char &c = board[i][j];
            cin >> c;
            if (c == 'X') {
                asd[j].insert(i);
            }
        }
    }
    for (int j = 0; j < m; ++j) asd[j].insert(n);
    int amt;
    cin >> amt;
    for (int i = 0; i < amt; ++i) {
        int it;
        cin >> it;
        int y = 0;
        int x = it - 1;
        for (;;)
        {
            auto it = asd[x].lower_bound(y);
            y = *it - 1;
            if (y + 1 == n) break;
            else if (board[y + 1][x] == 'O') {
                if (isfree(y + 1, x - 1) && isfree(y, x - 1)) {
                    x--;
                    y++;
                }
                else if (isfree(y, x + 1) && isfree(y + 1, x + 1)) {
                    x++;
                    y++;
                }
                else break;
            }
            else break;
        }
        asd[x].insert(y);
        board[y][x] = 'O';
    }
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            putchar_unlocked(board[i][j]);
        }
        putchar_unlocked('\n');
    }
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: TIME LIMIT EXCEEDED