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Copy pathMergeSort.java
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50 lines (41 loc) · 1.42 KB
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package sort;
import java.util.Arrays;
/**
* Created by TommyYang on 2018/3/12.
*/
public class MergeSort implements IArraySort {
@Override
public int[] sort(int[] sourArr) throws Exception {
// 对 sourceArr 进行拷贝，不改变参数内容
int[] desArr = Arrays.copyOf(sourArr, sourArr.length);
if (desArr.length < 2) {
return desArr;
}
int middle = (int) Math.floor(desArr.length / 2);
int[] left = Arrays.copyOfRange(desArr, 0, middle);
int[] right = Arrays.copyOfRange(desArr, middle, desArr.length);
return this.merge(sort(left), sort(right));
}
protected int[] merge(int[] left, int[] right) {
int[] result = new int[left.length + right.length];
int i = 0;
while (left.length > 0 && right.length > 0) {
if (left[0] <= right[0]) {
result[i++] = left[0];
left = Arrays.copyOfRange(left, 1, left.length);
} else {
result[i++] = right[0];
right = Arrays.copyOfRange(right, 1, right.length);
}
}
while (left.length > 0) {
result[i++] = left[0];
left = Arrays.copyOfRange(left, 1, left.length);
}
while (right.length > 0) {
result[i++] = right[0];
right = Arrays.copyOfRange(right, 1, right.length);
}
return result;
}
}