Kamen

#include <bits/stdc++.h>
#define pii pair<int, int>
#define F first
#define S second

using namespace std;

char c[31][30001];

int w, h;
vector<int> d[31][30001];
pii p[31], r[31][30001];

bool ok(char a, char b){return a=='.' && b=='.';}

pii fall(int x, int y){
    if(c[x][y+1] == 'X' && y<h) return {x, y};
    if(ok(c[x][y+1], c[x][y+1]) && y<h) return {x, y+1};
    if(ok(c[x-1][y], c[x-1][y+1]) && y<h && x>1) return {x-1, y+1};
    if(ok(c[x+1][y], c[x+1][y+1]) && y<h && x<w) return {x+1, y+1};
    return {x, y};
}

void drop(int f, bool yee){
    int x = p[f].F, y = p[f].S;
    vector<pair<int, bool> > e;

    pii prev = r[x][y];

    while(1){

        if(d[x][y].size()){
            for(auto i:d[x][y]) e.push_back({i, 1});
            d[x][y].clear();
        }

        pii next = fall(x, y);
        if(x == next.F && y == next.S) break;

        for(int i=e.size()-1; e[i].S; i--) e[i].S = 0;

        prev = r[next.F][next.S];
        r[next.F][next.S] = {x, y};
        x = next.F;
        y = next.S;
    }
    if(yee){
        for(auto i:e){
            d[x][y].push_back(i.F);
            p[i.F] = {x, y};
        }
        return;
    } else {
        for(auto i:e){
            if(i.S){
                d[prev.F][prev.S].push_back(i.F);
                p[i.F] = prev;
            }
            else {
                d[r[x][y].F][r[x][y].S].push_back(i.F);
                p[i.F] = r[x][y];
            }
        }
    }
    c[x][y] = 'O';

}

int main(){

    cin >> h >> w;

    for(int i=1; i<=h; i++){
        for(int j=1; j<=w; j++){
            cin >> c[j][i];
        }
    }

    for(int i=1; i<=w; i++){
        p[i] = {i, 0};
        r[i][0] = {-1e9, 0};
        d[i][0].push_back(i);
        if(p[i].F > 0) drop(i, 1);
    }

    int n;
    cin >> n;

    for(int i=0; i<n; i++){
        int x;
        cin >> x;
        drop(x, 0);
    }

    for(int i=1; i<=h; i++){
        for(int j=1; j<=w; j++){
            cout << c[j][i];
        }
        cout << '\n';
    }

    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: RUNTIME ERROR

Test 10

Verdict: RUNTIME ERROR