8000 1，给Vector添加equals和hashCode方法。 · mapengfei00099/javaalgorithm@e3de22f · GitHub
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shengshijun
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1，给Vector添加equals和hashCode方法。
2，完成从一个连续数组中查找连续子数组其和为指定值。
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‎src/main/java/ssj/algorithm/collections/Vector.java

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@@ -145,6 +145,25 @@ public String toString() {
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return sb.toString();
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}
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@Override
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public boolean equals(Object o) {
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if (this == o) return true;
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if (o == null || getClass() != o.getClass()) return false;
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@SuppressWarnings("unchecked")
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Vector vector = (Vector) o;
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// Probably incorrect - comparing Object[] arrays with Arrays.equals
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if (!Arrays.equals(_values, vector._values)) return false;
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return true;
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}
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@Override
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public int hashCode() {
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return _values != null ? Arrays.hashCode(_values) : 0;
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}
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public void swap(int start, int end) {
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ArrayUtil.swap(_values, start, end);
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}

‎src/main/java/ssj/algorithm/math/MathUtil.java

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@@ -2,6 +2,8 @@
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import com.google.common.base.Preconditions;
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import ssj.algorithm.ArrayUtil;
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import ssj.algorithm.List;
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import ssj.algorithm.collections.Vector;
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import ssj.algorithm.lang.Tuple2;
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import java.math.BigInteger;
@@ -398,4 +400,36 @@ private static boolean checkUnique(int[] arr, int ele) {
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}
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return count == 1;
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}
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/**
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* 在一个排好序的int数组中查找连续子数组其和为指定的值。
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* @param arr
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* @param value
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* @return
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*/
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public static List<Tuple2<Integer, Integer>> findSumInOrder(int[] arr, int value) {
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Preconditions.checkNotNull(arr);
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Preconditions.checkArgument(arr.length > 1);
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List<Tuple2<Integer, Integer>> result = new Vector<>();
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int start = arr.length - 2;
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int end = arr.length - 1;
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int sum = arr[start] + arr[end];
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while (start >= 0) {
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if (sum == value) {
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result.add(new Tuple2<>(start, end));
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sum -= arr[end];
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end--;
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} else if (sum < value) {
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start--;
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if (start >= 0) {
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sum += arr[start];
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}
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} else {
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sum -= arr[end];
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end--;
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}
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}
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return result;
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}
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}

‎src/test/java/ssj/algorithm/math/MathUtilTest.java

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@@ -85,4 +85,10 @@ public void testUniqueInt() {
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assertEquals(2, MathUtil.uniqueInt(new int[]{100, 100, 3, 4, 5, 2, 3, 4, 5}));
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assertEquals(new Tuple2<>(2, 100), MathUtil.uniqueTwoInt(new int[]{100, 3, 4, 5, 2, 3, 4, 5}));
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}
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@Test
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public void testFindSumInOrder() {
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System.out.println(MathUtil.findSumInOrder(new int[]{1, 2, 3, 4, 5, 6, 7, 8}, 15));
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System.out.println(MathUtil.findSumInOrder(new int[]{1,4,7,8,11}, 20));
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}
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}

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