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#include <iostream>
#include <vector>
#include <queue>

struct Color {
    int x1 = 60;
    int x2 = -1;
    int y1 = 60;
    int y2 = -1;
    
    void insert(int x, int y) {
        x1 = std::min(x1, x);
        x2 = std::max(x2, x);
        y1 = std::min(y1, y);
        y2 = std::max(y2, y);
    }
    
    bool contains(int x, int y) {
        if (x < x1 || x > x2) {
            return false;
        }
        if (y < y1 || y > y2) {
            return false;
        }
        return true;
    }
};

class Solution {
public:
    bool isPrintable(std::vector<std::vector<int>>& targetGrid) {
        int num = 60;
        int maxn = -1;
        int m = targetGrid.size();
        int n = targetGrid[0].size();
        std::vector<Color> colors(num);
        
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                int c = targetGrid[i][j] - 1;
                maxn = std::max(c, maxn);
                colors[c].insert(i, j);
            }
        }
        ++maxn;
        
        std::vector<std::vector<int>> adj(maxn, std::vector<int>(maxn, false));
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                int c = targetGrid[i][j] - 1;
                for (int d = 0; d < maxn; ++d) {
                    if (colors[d].contains(i, j)) {
                        adj[d][c] = true;
                    }
                }
            }
        }
        
        int cnt = 0;
        std::vector<int> inDegree(maxn, 0);
        for (int i = 0; i < maxn; ++i) {
            for (int j = 0; j < maxn; ++j) {
                if (adj[i][j] && i != j) {
                    ++inDegree[j];
                }
            }
        }
        
        std::queue<int> q;
        for (int i = 0; i < maxn; ++i) {
            if (inDegree[i] == 0) {
                q.push(i);
            }
        }
        
        while (!q.empty()) {
            int i = q.front();
            q.pop();
            ++cnt;
            for (int j = 0; j < maxn; ++j) {
                if (!adj[i][j] || i == j) {
                    continue;
                }
                --inDegree[j];
                if (inDegree[j] == 0) {
                    q.push(j);
                }
            }
        }
        
        return cnt == maxn;
    }
};