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package class_2022_04_2_week;
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// 来自阿里
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// x = { a, b, c, d }
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// y = { e, f, g, h }
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// x、y两个小数组长度都是4
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// 如果有: a + e = b + f = c + g = d + h
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// 那么说x和y是一个完美对
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// 题目给定N个小数组，每个小数组长度都是K
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// 返回这N个小数组中，有多少完美对
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// 本题测试链接 : https://www.nowcoder.com/practice/f5a3b5ab02ed4202a8b54dfb76ad035e
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// 提交以下所有代码，把主类名改成Main
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// 请同学们务必参考如下代码中关于输入、输出的处理
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// 这是输入输出处理效率很高的写法
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// 可以直接通过
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import java.io.BufferedReader;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.io.OutputStreamWriter;
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import java.io.PrintWriter;
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import java.io.StreamTokenizer;
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import java.util.HashMap;
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public class Code06_PerfectPairNumber {
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public static void main(String[] args) throws IOException {
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BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
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StreamTokenizer in = new StreamTokenizer(br);
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PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
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while (in.nextToken() != StreamTokenizer.TT_EOF) {
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int n = (int) in.nval;
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in.nextToken();
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int m = (int) in.nval;
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int[][] matrix = new int[n][m];
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < m; j++) {
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in.nextToken();
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matrix[i][j] = (int)in.nval;
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}
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}
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long ans = perfectPairs(matrix);
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out.println(ans);
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out.flush();
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}
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}
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public static long perfectPairs(int[][] matrix) {
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long ans = 0;
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// key : 字符串 特征，差值特征 : "_5_-2_6_9"
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HashMap<String, Integer> counts = new HashMap<>();
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for (int[] arr : matrix) {
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StringBuilder self = new StringBuilder();
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StringBuilder minus = new StringBuilder();
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for (int i = 1; i < arr.length; i++) {
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self.append("_" + (arr[i] - arr[i - 1]));
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minus.append("_" + (arr[i - 1] - arr[i]));
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}
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ans += counts.getOrDefault(minus.toString(), 0);
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counts.put(self.toString(), counts.getOrDefault(self.toString(), 0) + 1);
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}
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return ans;
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}
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} |
