74 lines
1.6 KiB
JavaScript
74 lines
1.6 KiB
JavaScript
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const fs = require('fs/promises');
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let answer = 0;
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const rotate90 = (matrix) => {
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const result = matrix[matrix.length - 1].map(x => [x]) ;
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for (const row of (matrix.slice(0, -1).reverse())) {
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for(const [i, columns] of result.entries()) {
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columns.push(row[i]);
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}
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};
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return result;
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}
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const isVisible = (matrix, rotatedMatrix, x, y) => {
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const height = matrix[y][x];
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const rY = x;
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const rX = matrix.length - y - 1;
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const left = matrix[y].slice(0, x);
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if(Math.max(...left) < height) {
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return 1;
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}
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const right = matrix[y].slice(x + 1);
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if(Math.max(...right) < height) {
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return 1;
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}
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const bottom = rotatedMatrix[rY].slice(0, rX);
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if(Math.max(...bottom) < height) {
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return 1;
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}
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const top = rotatedMatrix[rY].slice(rX + 1);
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if(Math.max(...top) < height) {
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return 1;
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}
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return 0;
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};
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//1234
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//5678
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//9012
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const countVisible = (matrix) => {
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return matrix.reduce((count, row) => {
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const [_, rowCount] = row.reduce(([tallest, count], tree) => {
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return [Math.max(tree, tallest), tree > tallest ? count+1: count];
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}, [-1, 0]);
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return count + rowCount;
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},0);
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}
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(async () => {
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const input = await fs.readFile("./input.txt", 'utf8');
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//const input = "1234\n5678\n9012";
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const lines = input.split("\n");
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const matrix = lines.map(line => line.split("").map(x => parseFloat(x))).filter(x => x.length);
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const rotatedMatrix = rotate90(matrix);
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for(let y = 0; y < matrix.length; ++y) {
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for(let x = 0; x < matrix[0].length; ++x) {
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if(isVisible(matrix, rotatedMatrix, x, y)) {
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++answer
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}
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}
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}
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console.log(answer);
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})();
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