同样，用最简单的遍历还是只能拿70分，想要拿满得用前缀和、后缀和

代码实现

#include 
#include  
#include 
#include 
#include 
using namespace std;

int main() {
	// 提高cin,cout的速度
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	map<int, int> succeed, fail, total_succeed, total_fail;
	set<int> scores;
	int n;
	cin >> n;
	int score;
	bool not_failed;
	while (n--) {
		cin >> score >> not_failed;
		if (not_failed) succeed[score]++;
		else fail[score]++;
		scores.emplace(score); 
	}
	int pre = 0;
	for (auto it = scores.rbegin(); it != scores.rend(); it++) {
		total_succeed[*it] = succeed[*it] + pre;
		pre += succeed[*it];
	}
	pre = 0;
	for (auto it = scores.begin(); it != scores.end(); it++) {
		total_fail[*it] = fail[*it] + pre;
		pre += fail[*it];
	}
	int best = 0, curr_predict = 0, best_predict = 0;
	for (auto s : scores) {
		curr_predict = total_succeed[s] + total_fail[s] - fail[s];
		if (curr_predict >= best_predict) {
			best = s;
			best_predict = curr_predict;
		}
	}
	cout << best;
	return 0;
}
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