1 #include<bits/stdc++.h>
2 using namespace std;
3
4 struct node {
5 int y,result;
6 };
7 vector<node> nodes;
8
9 bool cmp(node &a,node &b) {
10 if(a.y != b.y) return a.y < b.y;
11 else return a.result < b.result;
12 }
13 vector<long int> cnt_0,cnt_1;
14 int main() {
15 int m,y,result;
16 scanf("%d",&m);
17 for(int i = 0 ; i < m; ++i) {
18 scanf("%d%d",&y,&result);
19 nodes.push_back({y,result});
20 }
21 sort(nodes.begin(),nodes.end(),cmp); //先对输入排序
22
23 //cnt_0存储y前面result为0的个数
24 //cnt_1存储y前面result为1的个数
25 cnt_0.resize(m);
26 cnt_1.resize(m);
27 if(nodes[0].result == 0) {
28 cnt_0[0] = 1;
29 cnt_1[0] = 0;
30 } else {
31 cnt_0[0] = 0;
32 cnt_1[0] = 1;
33 }
34 for(int i = 1; i < nodes.size(); ++i) {
35 if(nodes[i].result == 0) {
36 cnt_0[i] = cnt_0[i-1] + 1;
37 cnt_1[i] = cnt_1[i-1];
38 } else {
39 cnt_1[i] = cnt_1[i-1] + 1;
40 cnt_0[i] = cnt_0[i-1];
41 }
42 }
43
44 // 初始化
45 int final_y = nodes[0].y;
46 long int final_cnt = cnt_1[m-1];
47
48 for(int i = 1; i < m; ++i) {
49 long int current_cnt = 0;
50 while(nodes[i].y == nodes[i-1].y && i < m) //如果前面计算过y，则跳过
51 ++i;
52 current_cnt = cnt_0[i-1] + cnt_1[m-1] - cnt_1[i-1]; //y的正确预测次数 = y前面result为0的个数 + y以及y后面result为1的个数
53 if(current_cnt >= final_cnt) {
54 final_cnt = current_cnt;
55 final_y = nodes[i].y;
56 }
57 }
58 printf("%d",final_y);
59 return 0;
60 }
