GCJ2018-2T1: Falling Balls

#include <bits/stdc++.h>
using namespace std;

const int N = 100;

int tr[N + 10];

int main(){

    int Q;
    scanf("%d", &Q);
    for(int q = 1; q <= Q; ++q){
        cout << "Case #" << q << ": ";
        char board[N + 10][N + 10] = {};
        int col;
        scanf("%d", &col);
        for(int i = 1; i <= col; ++i){
            scanf("%d", &tr[i]);
        }
        if(tr[1] == 0 || tr[col] == 0){
            cout << "IMPOSSIBLE\n";
            continue;
        }
        int bIdx = 1;
        int tIdx = 1;
        int currRow = 0;
        while(bIdx < col){
            if(tr[tIdx] == 0){
                ++tIdx;
                continue;
            }
            if(tIdx < bIdx){
                int i = 1;
                for(int j = bIdx; j > tIdx; --j){
                    board[i][j] = '/';
                    currRow = max(currRow, i);
                    ++i;
                }
            } else if(tIdx > bIdx){
                int i = 1;
                for(int j = bIdx; j < tIdx; ++j){
                    board[i][j] = '\\';
                    currRow = max(currRow, i);
                    ++i;
                }
            }
            --tr[tIdx];
            ++bIdx;
        }
        cout << currRow + 1 << '\n';
        for(int i = 1; i <= currRow + 1; ++i){
            for(int j = 1; j <= col; ++j){
                if(board[i][j] == '\0'){
                    cout << '.';
                } else {
                    cout << board[i][j];
                }
            }
            cout << '\n';
        }
    }

    return 0;
}