alert("I have written the code for 3×3 grid checking by trial & errors & by reading a medium article.\nhttps://link.medium.com/K7F71zQgrV"); window.onload = () => { document.querySelector("#validateBtn") .addEventListener("click", validate); document.querySelector("#loadRandomBtn") .addEventListener("click", randomTable); const table = document.createElement("table"); for(let i = 0; i < 9; i++) { const tr = document.createElement("tr"); for(let j = 0; j < 9; j++) { const td = document.createElement("td"); const input = document.createElement("input"); input.type = "number"; input.value = Math.ceil(Math.random() * 9); td.appendChild(input); tr.appendChild(td); } table.appendChild(tr); } document.body.insertBefore(table, document.querySelector("div")); } function validate() { const inputs = document.querySelectorAll("input"); inputs.forEach(input => input.value = input.value[0]); const table = [] for(let i = 0; i < 9; i++) { table[i] = []; for(let j = 0; j < 9; j++) { table[i][j] = parseInt(+inputs[j + 9 * i].value); } } let index = 0; for(let i = 0; i < 9; i++) { const row = table[i]; for(let j = 0; j < 9; j++) { const block = []; for(let a = 0; a < 3; a++) { for(let b = 0; b < 3; b++) { block.push(table[a + Math.floor(i/3) * 3][b + Math.floor(j/3) * 3]); } } let cellVal = row[j]; const column = table.map(row => row[j]); let color = ''; if(cellVal < 1) { color = "#f00" } else if(count(cellVal, row) == 1 && count(cellVal, column) == 1 && count(cellVal, block) == 1) { color = "#8f8"; } else { color = "#f88"; } inputs[index++].style.background = color; } } } function count(n, arr) { let count = 0; for(let i = 0; i < arr.length; i++) { if(n === arr[i]) { count++; } } return count; } function randomTable() { document.querySelectorAll("input") .forEach(input => { input.style.background = "none"; input.value = Math.ceil(Math.random() * 9); }); } /* function makeSudoku() { } */

[C39] Sudoku Validator