28 lines
898 B
Java
28 lines
898 B
Java
package quant.rich.emoney.util;
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import java.util.*;
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public class ChunkRandomIter {
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final static Random RANDOM = new Random();
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public static <T> List<T> splitShuffleAndFlatten(List<T> list, int n) {
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int size = list.size();
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if (n <= 0) throw new IllegalArgumentException("n must be > 0");
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n = Math.min(n, size == 0 ? 1 : size);
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List<T> parts = new ArrayList<>(n);
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int base = size / n; // 每份至少 base 个
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int extra = size % n; // 前 extra 份多一个
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int idx = 0;
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for (int i = 0; i < n; i++) {
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int partSize = base + (i < extra ? 1 : 0);
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List<T> part = new ArrayList<>(list.subList(idx, idx + partSize));
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Collections.shuffle(part, RANDOM);
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parts.addAll(part);
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idx += partSize;
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}
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return parts;
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}
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} |