Language: C++

#include <iostream>
#include <stack>
using namespace std;

#define N 10
struct point{
    int x, y, size;
};

int n;
int total_drop = 0;
int cloth[N][N];
int smallx[4] = {1, -1, 0, 0};
int smally[4] = {0, 0, 1, -1};
int midx[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int midy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
int bigx[12] = {-2, -1, -1, -1, 0, 0, 0, 0, 1, 1, 1, 2};
int bigy[12] = {0, -1, 0, 1, -2, -1, 1, 2, -1, 0, 1, 0};
stack<point> st;

bool can_drop_big(int x, int y){
    for (int i = 0; i < 12; i++) {
        int mx = x + bigx[i];
        int my = y + bigy[i];
        if (mx < 0 || mx >= N || my < 0 || my >= N) {
            return false;
        }
        if (cloth[my][mx] == 0) {
            return false;
        }
    }
    return true;
}

bool can_drop_mid(int x, int y){
    for (int i = 0; i < 8; i++) {
        int mx = x + midx[i];
        int my = y + midy[i];
        if (cloth[my][mx] == 0) {
            return false;
        }
    }
    return true;
}

bool can_drop_small(int x, int y){
    for (int i = 0; i < 4; i++) {
        int mx = x + smallx[i];
        int my = y + smally[i];
        if (cloth[my][mx] == 0) {
            return false;
        }
    }
    return true;
}

void del_big(int x, int y){
    cloth[y][x]--;
    for (int i = 0; i < 12; i++) {
        int mx = x + bigx[i];
        int my = y + bigy[i];
        cloth[my][mx]--;
    }
}

void del_mid(int x, int y){
    cloth[y][x]--;
    for (int i = 0; i < 8; i++) {
        int mx = x + midx[i];
        int my = y + midy[i];
        cloth[my][mx]--;
    }
}

void del_small(int x, int y){
    cloth[y][x]--;
    for (int i = 0; i < 4; i++) {
        int mx = x + smallx[i];
        int my = y + smally[i];
        cloth[my][mx]--;
    }
}

void dfs(int drop_num, int ink_num){
    if (drop_num == n) {
        if (ink_num == total_drop) {
            while (!st.empty()) {
                point p = st.top();
                cout << p.x << " " << p.y << " " << p.size << endl;
                st.pop();
            }
        }
        return;
    }
    int cloth_cp[N][N];
    for (int y = 1; y < N - 1; y++) {
        for (int x = 1; x < N - 1; x++) {
            if (cloth[y][x] == 0) {
                continue;
            }
            if (can_drop_big(x, y)) {
                memcpy(cloth_cp, cloth, sizeof(cloth));
                del_big(x, y);
                st.push(point({x, y, 3}));
                dfs(drop_num + 1, ink_num + 13);
                if (st.empty()) {
                    return;
                }
                st.pop();
                memcpy(cloth, cloth_cp, sizeof(cloth));
            }
            
            if (can_drop_mid(x, y)) {
                memcpy(cloth_cp, cloth, sizeof(cloth));
                del_mid(x, y);
                st.push(point({x, y, 2}));
                dfs(drop_num + 1, ink_num + 9);
                if (st.empty()) {
                    return;
                }
                st.pop();
                memcpy(cloth, cloth_cp, sizeof(cloth));
            }
            
            if (can_drop_small(x, y)) {
                memcpy(cloth_cp, cloth, sizeof(cloth));
                del_small(x, y);
                st.push(point({x, y, 1}));
                dfs(drop_num + 1, ink_num + 5);
                if (st.empty()) {
                    return;
                }
                st.pop();
                memcpy(cloth, cloth_cp, sizeof(cloth));
            }
            
        }
    }
    
}

int get_drop_ink_num(){
    int count = 0;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            if (cloth[i][j] >= 0) {
                count += cloth[i][j];
            }
        }
    }
    return count;
}

int main()
{
    cin >> n;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            cin >> cloth[i][j];
        }
    }
    total_drop = get_drop_ink_num();
    dfs(0, 0);
    return 0;
}

Compiler output:
a.cc: In function 'void dfs(int, int)':
a.cc:102:17: error: 'memcpy' was not declared in this scope
  102 |                 memcpy(cloth_cp, cloth, sizeof(cloth));
      |                 ^~~~~~
a.cc:3:1: note: 'memcpy' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    2 | #include <stack>
  +++ |+#include <cstring>
    3 | using namespace std;
a.cc:114:17: error: 'memcpy' was not declared in this scope
  114 |                 memcpy(cloth_cp, cloth, sizeof(cloth));
      |                 ^~~~~~
a.cc:114:17: note: 'memcpy' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc:126:17: error: 'memcpy' was not declared in this scope
  126 |                 memcpy(cloth_cp, cloth, sizeof(cloth));
      |                 ^~~~~~
a.cc:126:17: note: 'memcpy' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'