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47 lines
1.3 KiB
47 lines
1.3 KiB
package 第01期.mca_test;
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import java.util.Arrays;
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// 本题测试链接 : https://leetcode.com/problems/closest-subsequence-sum/
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// 本题数据量描述:
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// 1 <= nums.length <= 40
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// -10^7 <= nums[i] <= 10^7
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// -10^9 <= goal <= 10^9
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// 通过这个数据量描述可知，需要用到分治，因为数组长度不大
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// 而值很大，用动态规划的话，表会爆
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public class Code06_ClosestSubsequenceSum {
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public static int[] l = new int[1 << 20];
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public static int[] r = new int[1 << 20];
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public static int minAbsDifference(int[] nums, int goal) {
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if (nums == null || nums.length == 0) {
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return goal;
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}
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int le = process(nums, 0, nums.length >> 1, 0, 0, l);
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int re = process(nums, nums.length >> 1, nums.length, 0, 0, r);
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Arrays.sort(l, 0, le);
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Arrays.sort(r, 0, re--);
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int ans = Math.abs(goal);
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for (int i = 0; i < le; i++) {
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int rest = goal - l[i];
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while (re > 0 && Math.abs(rest - r[re - 1]) <= Math.abs(rest - r[re])) {
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re--;
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}
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ans = Math.min(ans, Math.abs(rest - r[re]));
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}
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return ans;
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}
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public static int process(int[] nums, int index, int end, int sum, int fill, int[] arr) {
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if (index == end) {
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arr[fill++] = sum;
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} else {
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fill = process(nums, index + 1, end, sum, fill, arr);
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fill = process(nums, index + 1, end, sum + nums[index], fill, arr);
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}
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return fill;
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}
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}
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