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package class14;
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import java.util.PriorityQueue;
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public class Code02_LessMoneySplitGold {
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// 纯暴力！
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public static int lessMoney1(int[] arr) {
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if (arr == null || arr.length == 0) {
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return 0;
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}
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return process(arr, 0);
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}
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// 等待合并的数都在arr里，pre之前的合并行为产生了多少总代价
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// arr中只剩一个数字的时候，停止合并，返回最小的总代价
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public static int process(int[] arr, int pre) {
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if (arr.length == 1) {
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return pre;
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}
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int ans = Integer.MAX_VALUE;
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for (int i = 0; i < arr.length; i++) {
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for (int j = i + 1; j < arr.length; j++) {
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ans = Math.min(ans, process(copyAndMergeTwo(arr, i, j), pre + arr[i] + arr[j]));
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}
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}
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return ans;
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}
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public static int[] copyAndMergeTwo(int[] arr, int i, int j) {
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int[] ans = new int[arr.length - 1];
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int ansi = 0;
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for (int arri = 0; arri < arr.length; arri++) {
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if (arri != i && arri != j) {
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ans[ansi++] = arr[arri];
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}
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}
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ans[ansi] = arr[i] + arr[j];
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return ans;
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}
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public static int lessMoney2(int[] arr) {
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PriorityQueue<Integer> pQ = new PriorityQueue<>();
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for (int i = 0; i < arr.length; i++) {
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pQ.add(arr[i]);
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}
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int sum = 0;
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int cur = 0;
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while (pQ.size() > 1) {
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cur = pQ.poll() + pQ.poll();
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sum += cur;
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pQ.add(cur);
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}
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return sum;
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}
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// for test
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public static int[] generateRandomArray(int maxSize, int maxValue) {
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int[] arr = new int[(int) ((maxSize + 1) * Math.random())];
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for (int i = 0; i < arr.length; i++) {
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arr[i] = (int) (Math.random() * (maxValue + 1));
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}
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return arr;
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}
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public static void main(String[] args) {
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int testTime = 100000;
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int maxSize = 6;
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int maxValue = 1000;
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for (int i = 0; i < testTime; i++) {
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int[] arr = generateRandomArray(maxSize, maxValue);
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if (lessMoney1(arr) != lessMoney2(arr)) {
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System.out.println("Oops!");
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}
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}
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System.out.println("finish!");
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}
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}
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