【414.干草堆】

干草堆

#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;

typedef long long ll;
typedef pair<int, int> PII;

const int N = 1e6 + 10;
const int mod = 1e9 + 7;


ll res, cnt;
int n, m;
int x, y;

int b[N];

int main()
{
    cin >> n >> m;

    while (m -- )
    {
        cin >> x >> y;
        b[x] ++, b[y + 1] --; // 建立差分数组
    }

    for (int i = 1; i <= n; i ++ ) b[i] += b[i - 1]; // 求原数组

    nth_element(b + 1, b + n / 2 + 1, b + n + 1); // 求中位数

    cout << b[n / 2 + 1];


    return 0;
}