LeetCode-面試題 16.19. 水域大小

你有一個用於表示一片土地的整數矩陣land，該矩陣中每個點的值代表對應地點的海拔高度。若值爲0則表示水域。由垂直、水平或對角連接的水域爲池塘。池塘的大小是指相連接的水域的個數。編寫一個方法來計算矩陣中所有池塘的大小，返回值需要從小到大排序。

示例：

輸入：
[
  [0,2,1,0],
  [0,1,0,1],
  [1,1,0,1],
  [0,1,0,1]
]
輸出： [1,2,4]
提示：

0 < len(land) <= 1000
0 < len(land[i]) <= 1000

 

深度優先搜索DFS：

#include <iostream>
#include <vector>
#include <string.h>
#include <algorithm>
using namespace std;

class Solution {
public:
    vector<int> pondSizes(vector<vector<int>>& land) {

        memset(tag,0x00,sizeof(tag));
        for(int i=0;i<land.size();i++){
            for(int j=0;j<land[i].size();j++){
                if(land[i][j]==0 && tag[i][j]==0){
                    int tmp = DFS(land,i,j);
                    res.push_back(tmp);
                }
            }
        }

        sort(res.begin(),res.end());
        return res;
    }

private:
    vector<int> res;
    int tag[1001][1001];

    int DFS(vector<vector<int>>& land,int x,int y){

        if(x<0||x>=land.size()){
            return 0;
        }
        if(y<0||y>=land[x].size()){
            return 0;
        }
        if(tag[x][y]){
            return 0;
        }
        if(land[x][y]!=0){
            return 0;
        }

        int num = 1;
        tag[x][y]=1;

        num+=DFS(land,x+1,y-1);
        num+=DFS(land,x-1,y+1);
        num+=DFS(land,x,y+1);
        num+=DFS(land,x,y-1);
        num+=DFS(land,x+1,y);
        num+=DFS(land,x-1,y);
        num+=DFS(land,x-1,y-1);
        num+=DFS(land,x+1,y+1);

        return num;

    }
};

int main(){
    //    vector<vector<int>> land = {{0,2,1,0},
    //                                {0,1,0,1},
    //                                {1,1,0,1},
    //                                {0,1,0,1}};

    vector<vector<int>> land = {{2,8,8,4,1,7,1,5,4,2,0,8,1,9,2,5,6,9,7,4,8,9,1,7,3,6,9,3,7,1,5,7,3,1,9,9,9,6,5,1,9,9,4,1,6,4,7,6,1,6,1,3,3,9,0,3,0,0,0,1,3,1,2,0,0,0,3,2,7,3,6,7,9},{2,0,9,8,2,0,5,8,4,0,4,5,2,1,5,6,0,6,3,3,6,9,5,4,0,9,4,7,1,4,2,8,9,8,0,6,3,5,7,2,1,6,8,4,8,4,6,5,0,3,7,1,7,6,3,0,2,2,2,3,2,4,7,7,6,8,2,9,2,5,0,3,8},{2,7,0,1,1,3,6,5,6,0,7,0,2,4,5,0,3,7,3,1,5,7,9,8,8,0,9,8,1,9,4,7,5,6,5,4,1,7,7,4,4,3,8,3,5,3,3,8,7,4,5,4,8,0,2,0,4,7,5,4,3,9,1,9,4,9,2,2,2,4,1,2,9},{6,0,4,4,6,7,8,8,9,9,5,4,9,7,0,4,2,7,1,9,2,2,9,2,4,3,0,5,1,7,8,9,0,5,3,3,3,1,1,7,1,2,7,5,6,8,7,2,3,1,5,3,5,7,9,7,7,8,8,7,2,4,4,2,8,2,3,2,1,9,1,2,7},{2,5,1,2,2,5,8,2,8,7,4,5,9,8,9,6,0,9,7,0,5,8,8,3,3,8,1,9,4,8,2,3,4,9,1,2,4,5,1,5,4,4,6,9,2,3,3,1,2,2,4,1,2,7,4,6,9,2,3,5,9,7,7,4,9,9,4,7,1,5,5,7,6},{9,9,9,1,8,3,3,4,6,5,7,7,3,1,1,3,9,2,7,0,6,8,8,0,2,9,6,6,4,4,6,2,6,6,1,7,5,6,4,9,6,9,8,2,1,4,3,4,6,6,8,6,4,7,8,3,7,1,3,7,5,3,2,1,4,7,9,7,3,4,9,0,1},{7,1,4,9,7,2,1,9,0,9,7,4,5,3,5,2,6,5,6,0,5,0,5,3,1,1,7,9,6,2,1,8,3,4,7,4,2,1,3,5,9,7,7,5,6,1,0,3,6,3,7,9,6,5,1,4,5,7,2,3,5,3,5,2,0,9,5,1,8,6,0,0,6},{7,9,9,8,8,3,9,7,5,1,1,8,4,4,6,3,7,2,1,9,5,6,1,2,2,5,6,3,9,6,7,9,2,7,1,4,7,3,5,0,1,2,2,5,4,9,3,1,2,1,1,0,5,1,8,4,2,1,2,4,5,4,5,6,8,7,7,4,8,3,2,7,9},{6,6,6,7,0,8,7,6,2,6,3,1,4,6,6,9,6,2,0,5,4,9,9,9,8,8,6,2,4,3,1,6,6,4,4,4,3,1,8,1,8,3,9,5,2,7,0,0,4,0,6,9,2,0,3,1,6,3,0,7,9,3,9,4,3,6,7,9,8,9,4,2,7},{7,8,1,8,5,3,5,1,2,9,6,2,8,7,9,7,7,8,6,3,4,4,3,2,8,6,5,7,8,5,7,5,8,3,9,6,8,9,6,6,8,7,4,9,4,6,1,1,6,7,5,6,7,0,3,3,9,3,6,1,3,8,1,2,8,3,3,6,7,9,4,4,1},{0,7,6,7,6,4,3,1,7,8,0,0,3,1,1,7,9,2,7,9,4,9,6,2,6,6,4,0,1,8,5,6,8,1,3,8,3,7,7,9,8,4,2,8,2,5,5,9,3,3,1,6,3,1,5,2,0,4,2,2,5,4,3,4,6,7,3,4,5,1,5,7,2},{1,7,7,6,3,4,1,8,4,3,9,8,1,5,5,4,7,7,1,8,5,7,6,4,2,6,7,7,1,3,1,7,4,8,5,2,3,9,1,2,8,2,2,0,4,5,6,1,0,4,4,2,4,9,2,4,8,2,5,5,8,2,4,8,9,3,9,1,4,5,5,5,1},{0,1,1,8,9,1,0,1,3,0,5,9,3,4,1,7,1,2,1,7,3,4,2,7,2,9,9,7,4,8,7,4,2,6,7,8,8,4,9,6,5,9,6,3,0,0,0,6,4,0,9,8,1,7,0,9,9,3,7,5,8,9,4,9,9,1,2,7,5,3,2,2,3},{8,8,1,9,4,8,6,7,4,8,7,7,3,1,6,2,6,3,2,8,4,9,3,5,3,7,1,1,3,7,5,6,6,1,9,3,0,6,1,7,5,1,8,1,6,7,1,8,2,2,0,5,1,0,7,6,7,9,3,2,7,8,5,5,2,1,2,3,0,1,5,0,7},{8,1,9,4,4,5,8,3,8,5,2,3,8,4,5,6,5,0,4,0,6,7,5,5,2,7,8,5,2,1,4,9,5,1,3,4,8,7,7,3,8,5,1,5,5,9,3,9,0,0,0,8,0,4,0,5,3,8,5,1,5,0,1,7,1,3,7,4,2,9,5,5,4},{5,3,5,5,4,4,1,5,6,1,7,4,0,7,5,8,0,3,6,7,0,4,4,8,3,2,6,3,8,0,9,8,9,9,3,2,7,6,9,6,3,1,8,8,6,4,9,4,4,2,7,5,0,1,5,0,8,9,4,1,6,9,8,7,0,1,7,3,4,6,1,1,8},{1,9,5,4,1,7,0,6,3,2,1,5,3,1,8,7,5,7,6,6,8,0,3,8,8,2,5,6,7,2,7,8,2,1,5,3,9,3,5,2,2,9,4,7,8,6,7,7,9,8,6,3,0,6,9,7,3,1,9,1,9,1,5,6,3,7,1,0,8,9,9,8,1},{5,8,5,7,7,8,0,7,9,2,0,4,5,8,8,7,8,6,5,4,6,3,4,1,7,2,8,7,4,7,5,2,5,5,9,3,3,7,1,6,5,1,9,5,5,5,6,2,1,3,6,8,1,0,5,2,8,8,9,9,3,0,5,3,3,8,1,4,5,8,3,2,7}};


    Solution *ps =new Solution();
    vector<int> res = ps->pondSizes(land);

    for(int i=0;i<res.size();i++){
        cout<<res[i]<<" ";
    }
    return 0;
}