标签：rom private each numbers gic only grid resin ali
A 3 x 3 magic square is a 3 x 3 grid filled with distinct numbers from 1 to 9 such that each row, column, and both diagonals all have the same sum.
Given an grid of integers, how many 3 x 3 "magic square" subgrids are there? (Each subgrid is contiguous).
3 x 3魔方是一个3 x 3网格，填充了从1到9的不同数字，这样每行，每列和两个对角线都具有相同的总和。给定一个整数网格，有多少个3 x 3“魔方”子网格？ （每个子网格都是连续的）。
Example 1:
Input: [[4,3,8,4],
[9,5,1,9],
[2,7,6,2]]
Output: 1
Explanation:
The following subgrid is a 3 x 3 magic square:
438
951
276
while this one is not:
384
519
762
In total, there is only one magic square inside the given grid.
Note:
1 <= grid.length <= 101 <= grid[0].length <= 100 <= grid[i][j] <= 151 class Solution { 2 public int numMagicSquaresInside(int[][] grid) { 3 int cnt=0; 4 for(int i=0;i<=grid.length-3;i++) 5 for(int j=0;j<=grid[0].length-3;j++) 6 if(helper(i,j,grid)) cnt++; 7 8 return cnt; 9 } 10 11 private boolean helper(int x,int y,int[][] grid){ 12 if(grid[x+1][y+1]!=5) return false; 13 14 int[] valid=new int[16]; 15 16 for(int i=x;i<=x+2;i++) 17 for(int j=y;j<=y+2;j++) 18 valid[grid[i][j]]++; 19 20 for (int v = 1; v <= 9; v++) 21 if (valid[v] != 1) return false; 22 23 if((grid[x][y]+grid[x][y+1]+grid[x][y+2])!=15) return false; 24 if((grid[x][y]+grid[x+1][y+1]+grid[x+2][y+2])!=15) return false; 25 if((grid[x][y]+grid[x+1][y]+grid[x+2][y])!=15) return false; 26 if((grid[x+2][y]+grid[x+2][y+1]+grid[x+2][y+2])!=15) return false; 27 if((grid[x][y+2]+grid[x+1][y+2]+grid[x+2][y+2])!=15) return false; 28 if((grid[x][y+2]+grid[x+1][y+1]+grid[x+2][y])!=15) return false; 29 return true; 30 } 31 }
标签：rom private each numbers gic only grid resin ali
原文地址：https://www.cnblogs.com/chanaichao/p/9608829.html
