78 lines
3.3 KiB
TypeScript
78 lines
3.3 KiB
TypeScript
// What is the greatest product of four adjacent numbers in the same direction (up, down, left, right, or diagonally) in the 20×20 grid?
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export {};
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const largestProductInGrid = (grid: number[][], adjacentDigits: number) => {
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let answer = 0;
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let product = 0;
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for (let i = 0; i < grid.length; i++) {
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const row = grid[i];
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for (let j = 0; j < row.length; j++) {
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if (j < row.length - adjacentDigits - 1) {
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// Horizontal
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product = grid[i][j];
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for (let k = 1; k < adjacentDigits; k++) {
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product *= grid[i][j + k];
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}
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}
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if (i < grid.length - adjacentDigits - 1) {
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// Vertical
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product = grid[i][j];
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for (let k = 1; k < adjacentDigits; k++) {
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product *= grid[i + k][j];
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}
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// Diagonally to the right
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if (j < row.length - adjacentDigits - 1) {
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product = grid[i][j];
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for (let k = 1; k < adjacentDigits; k++) {
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product *= grid[i + k][j + k];
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}
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}
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// Diagonally to the left
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if (j > adjacentDigits - 1) {
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product = grid[i][j];
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for (let k = 1; k < adjacentDigits; k++) {
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product *= grid[i + k][j - k];
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}
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}
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}
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answer = product > answer ? product : answer;
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}
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}
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return answer;
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};
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// Output
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const grid = [
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[8, 2, 22, 97, 38, 15, 0, 40, 0, 75, 4, 5, 7, 78, 52, 12, 50, 77, 91, 8],
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[49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 4, 56, 62, 0],
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[81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 3, 49, 13, 36, 65],
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[52, 70, 95, 23, 4, 60, 11, 42, 69, 24, 68, 56, 1, 32, 56, 71, 37, 2, 36, 91],
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[22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80],
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[24, 47, 32, 60, 99, 3, 45, 2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50],
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[32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70],
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[67, 26, 20, 68, 2, 62, 12, 20, 95, 63, 94, 39, 63, 8, 40, 91, 66, 49, 94, 21],
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[24, 55, 58, 5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72],
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[21, 36, 23, 9, 75, 0, 76, 44, 20, 45, 35, 14, 0, 61, 33, 97, 34, 31, 33, 95],
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[78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 3, 80, 4, 62, 16, 14, 9, 53, 56, 92],
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[16, 39, 5, 42, 96, 35, 31, 47, 55, 58, 88, 24, 0, 17, 54, 24, 36, 29, 85, 57],
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[86, 56, 0, 48, 35, 71, 89, 7, 5, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58],
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[19, 80, 81, 68, 5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 4, 89, 55, 40],
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[4, 52, 8, 83, 97, 35, 99, 16, 7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66],
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[88, 36, 68, 87, 57, 62, 20, 72, 3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69],
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[4, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18, 8, 46, 29, 32, 40, 62, 76, 36],
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[20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74, 4, 36, 16],
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[20, 73, 35, 29, 78, 31, 90, 1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 5, 54],
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[1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48]
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];
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const output = largestProductInGrid(grid, 4);
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console.log(output);
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