Online JudgeProblem SetAuthorsOnline ContestsUser
Web Board
F.A.Qs
Statistical Charts
Problems
Submit Problem
Online Status
Prob.ID:
Register
Authors ranklist
Current Contest
Past Contests
Scheduled Contests
Award Contest
Register

## JAVA 不会写C++二维数组排序...

Posted by SmartChen at 2018-11-20 22:17:13 on Problem 2549 and last updated at 2018-11-20 22:17:25
```package com.company;

import java.io.BufferedInputStream;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
static int[][]ab;
static int ans, cnt;
public static void main(String[] args) {
Scanner sc = new Scanner(new BufferedInputStream(System.in));
while (true) {
int N = sc.nextInt();
if (N == 0)
break;
int[] arr = new int[N];
for (int i = 0; i < arr.length; i++) {
arr[i] = sc.nextInt();
}
int SN = (N - 1) * N / 2;
ab = new int[SN][3];
//a + b = b - c
cnt = 0;
for (int i = 0; i < N; i++) {
for (int j = i + 1; j < N; j++) {
ab[cnt][0] = arr[i] + arr[j];
ab[cnt][1] = i;
ab[cnt++][2] = j;
}
}
Arrays.sort(ab, new Comparator<int[]>() {
@Override
public int compare(int[] o1, int[] o2) {
return o1[0] - o2[0];
}
});

ans = Integer.MIN_VALUE;
for (int i = 0; i < N; i++) {
for (int j = i + 1; j < N; j++) {
int c_d = arr[i] - arr[j];
f(i, j, c_d, arr[i]);
f(i, j, -c_d, arr[j]);
}
}
if (ans ==  Integer.MIN_VALUE)
System.out.println("no solution");
else
System.out.println(ans);
}
}
public static void f(int i, int j, int c_d, int d) {
int l = 0, r = cnt;
while (l < r - 1) {
int mid = (l + r) / 2;
if (ab[mid][0] < c_d )
l = mid;
else
r = mid;
}
for (int k = l + 1; k < cnt && ab[k][0] == c_d; k++) {
if (ab[k][2] == i || ab[k][2] == j || ab[k][1] == i || ab[k][1] == j) continue;
ans = Math.max(ans, d);
}
}
}```

Followed by: