66 lines
1.6 KiB
JavaScript
66 lines
1.6 KiB
JavaScript
import generate from Grid.Util;
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return {
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random: random
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};
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function random(size) {
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var indices = Array.from({length: size}).map(function(x, i) {return i;});
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var previousColumn;
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var columns = []
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while(columns.length < 8) {
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previousColumn = pickNextColumn(indices, previousColumn)
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columns.push(previousColumn);
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}
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return generate(size, size, function(cell) {
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return columns[cell.row] == cell.column;
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});
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}
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function pickNextColumn(columnsLeft, previousColumn) {
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var parts = contiguousParts(columnsLeft);
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if(parts.length == 1 && columnsLeft.length == 4) {
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var candidateColumns = [null, columnsLeft[1], columnsLeft[2], null];
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} else if(parts.length == 2 && columnsLeft.length < 5
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&& Math.min(parts[0].length, parts[1].length) < 2) {
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candidateColumns = parts[0].length == 1 ? [null].concat(parts[1]) : parts[0];
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} else {
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var candidateColumns = columnsLeft;
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}
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candidateColumns = candidateColumns.map(maskAround(previousColumn));
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return columnsLeft.splice(pickIndex(candidateColumns), 1)[0];
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}
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function maskAround(c0) {
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return function(c1) {
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return Math.abs(c1 - c0) < 2 ? null : c1;
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};
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}
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function pickIndex(t) {
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var o = {};
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var definedCount = 0;
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for(var i = 0; i < t.length; i++) {
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if(t[i] != undefined) {
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o[definedCount] = i;
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definedCount++;
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}
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}
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return o[Math.floor(definedCount * Math.random())];
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}
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function contiguousParts(t) {
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var parts = [];
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var current = [];
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for(var i = 0; i < t.length; i++) {
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if(current.length < 1 || t[i] - current[current.length-1] == 1) {
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current.push(t[i]);
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} else {
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parts.push(current);
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current = [t[i]];
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}
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}
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parts.push(current);
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return parts;
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}
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