Java代码

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();

        int[][] ints = new int[2][n + 1];
        ArrayList<Pair> pairs = new ArrayList<>();
        pairs.add(new Pair(-1,-1));

        for (int j = 1;j<=n;j++) {
            int x = sc.nextInt();
            int y = sc.nextInt();
            Pair pair = new Pair(x, y);
            pairs.add(pair);
        }



        Collections.sort(pairs, (o1,o2)-> {return o1.x-o2.x;});

        //构建前缀和
        for (int i = 0 ;i<2;i++) {
            for (int j = 1;j<=n;j++) {
                ints[i][j] = ints[i][j-1] + (pairs.get(j).y == i ? 1 : 0);
            }
        }

        int cnt = -1,res = 0;
        for (int i = 1 ;i<=n;i++) {
                int t = ints[0][i-1] + ints[1][n] - ints[1][i-1];
                if (t >= cnt) {cnt = t; res = pairs.get(i).x;}
            while (i+1<=n && pairs.get(i).x == pairs.get(i+1).x) i++;
        }

        System.out.println(res);
    }


    static class Pair {
        int x;
        int y;
        Pair(int x, int y) {
            this.x = x;
            this.y = y;
        }
    }


}