1765

class Solution {
public:
    vector<vector<int>> highestPeak(vector<vector<int>>& isWater) {
        int d[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};
        int rows = isWater.size(), cols = isWater[0].size();
        bool vis[rows][cols];
        memset(vis, 0, sizeof vis);
        vector<vector<int>> dist(rows, vector<int>(cols));
        queue<pair<int, int>> q;

        for(int i=0; i<rows; i++)
            for(int j=0; j<cols; j++){
                if(isWater[i][j]){
                    dist[i][j] = 0;
                    vis[i][j] = true;
                    q.push({i, j});
                }
            }

        while(!q.empty()){
            auto p = q.front();
            q.pop();
            for(int i=0; i<4; i++){
                int nextX = p.first+d[i][0], nextY = p.second+d[i][1];
                if(nextX < 0 || nextX >= rows || nextY < 0 || nextY >= cols || vis[nextX][nextY])
                    continue;
                vis[nextX][nextY] = true;
                dist[nextX][nextY] = dist[p.first][p.second]+1;
                q.push({nextX, nextY});
            }
        }

        return dist;
    }
};