codeforce C. Maximal Intersection

http://codeforces.com/contest/1029/problem/C

从第一天吃晚饭做到第二天吃完饭……你无法想象我的代码曾经150行 o(￣┰￣*)ゞ

找到所有线段最远的左边和最近的右边，当一个线段的左边或右边与上述重合就尝试删除。

import java.util.Arrays;
import java.util.Scanner;

public class A {
    public static void main(String[] args) {
        Scanner io = new Scanner(System.in);
        int n = io.nextInt();
        if (n == 1) {
            System.out.println(-(io.nextInt() - io.nextInt()));
            return;
        }
        int[] a = new int[n];
        int[] b = new int[n];
        int[] A = new int[n];
        int[] B = new int[n];
        int[] minLeft = new int[n];
        int[] minRight = new int[n];
        int[] maxLeft = new int[n];
        int[] maxRight = new int[n];
        
        for (int i = 0; i < n; i++) {
            A[i] = a[i] = io.nextInt();
            B[i] = b[i] = io.nextInt();
            if (i != 0) {
                maxLeft[i] = Math.max(maxLeft[i - 1], a[i]);
                minLeft[i] = Math.min(minLeft[i - 1], b[i]);
            } else {
                maxLeft[0] = a[0];
                minLeft[0] = b[0];
            }
        }
        for (int i = n - 1; i >= 0; i--) {
            if (i != n - 1) {
                maxRight[i] = Math.max(maxRight[i + 1], a[i]);
                minRight[i] = Math.min(minRight[i + 1], b[i]);
            } else {
                maxRight[n - 1] = a[n - 1];
                minRight[n - 1] = b[n - 1];
            }
        }
        Arrays.sort(A);
        Arrays.sort(B);

        int len = 0,min,max;
        for (int i = 0; i < n; i++) {
            if (a[i] == A[n - 1] || b[i] == B[0]) {
                if (i == 0) {
                    min = minRight[1];
                    max = maxRight[1];
                } else if (i == n - 1) {
                    min = minLeft[n - 2];
                    max = maxLeft[n - 2];
                } else {
                    min = Math.min(minLeft[i - 1], minRight[i + 1]);
                    max = Math.max(maxLeft[i - 1], maxRight[i + 1]);
                }
                len = Math.max(min - max, len);
            }
        }
        System.out.println(len);
    }
}