Sudoku
Description
Sudoku is a number-placement puzzle. The objective is to fill a 9 × 9 grid with digits so that each column, each row, and each of the nine 3 × 3 sub-grids that compose the grid contains all of the digits from 1 to 9.
This algorithm should check if the given grid of numbers represents a correct solution to Sudoku.
Example
For the first example below, the output should be true. For the other grid, the output should be false: each of the nine 3 × 3 sub-grids should contain all of the digits from 1 to 9.
Input/Output
-
[execution time limit] 4 seconds (js)
-
[input] array.array.integer grid
A matrix representing 9 × 9 grid already filled with numbers from 1 to 9.
- [output] boolean
true if the given grid represents a correct solution to Sudoku, false otherwise.
[JavaScript (ES6)] Syntax Tips
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// Prints help message to the console
// Returns a string
function helloWorld(name) {
console.log("This prints to the console when you Run Tests");
return "Hello, " + name;
}
Solution
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function sudoku(grid) {
return grid.every((row, i)=>{
return row.every((el,j)=>{
return grid.every((r,k)=>{
return (i == k || el !== grid[k][j]) &&
(j == k || el !== grid[i][k]);
});
});
}) && [0,1,2].every((i)=>[0,1,2].every(j=>{
var tmp = grid.slice(i*3,i*3+3).map(r=>r.slice(3*j, 3*j+3));
return tmp.reduce((a,b)=>a.concat(b)).filter((el,id,self)=>self.indexOf(el)===id).length === 9;
}));
}