洛谷__P10793 『SpOI - R1』Double Champions（贪心）

题目链接：P10793 『SpOI - R1』Double Champions - 洛谷

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题目大意：

有 $n$ 个区间和一个值 $w$，现在要将这 $n$ 个区间分成 $m$ 组，

使得每组内所有区间的交集的大小大于等于 $w$，求 $m$ 的最小值。

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代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<queue>
#include<deque>
#include<stack>
#include<set>
#include<map>
#include<unordered_set>
#include<unordered_map>
#include<bitset>
#include<tuple>
#include<array>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/hash_policy.hpp>
#include <ext/numeric>
#define inf 72340172838076673
#define int long long
#define endl '\n'
#define F first
#define S second
#define mst(a,x) memset(a,x,sizeof (a))
#define gmap __gnu_pbds::gp_hash_table
#define power __gnu_cxx::power
using namespace std;
typedef pair<int, int> pii;

const int N = 200086, mod = 998244353;

int n, m;

struct node {
    int l, r;
} e[N];

void solve() {

    cin >> n >> m;
    int mn = inf;
    for (int i = 1; i <= n; i++) {
        int a, b;
        cin >> a >> b;
        e[i] = {a, b};
        mn = min(mn, b - a + 1);
    }
    
    if (mn < m) {
        cout << "No" << endl;
        return;
    }
    
    if (m == 0) {
        cout << 1 << endl;
        return;
    }
    
    sort(e + 1, e + n + 1, [&](node a, node b) {
        return a.r < b.r;
    });
    
    int res = 0, mr = 0;
    for (int i = 1; i <= n; i++) {
        mr = min(mr, e[i].r);
        if (mr - e[i].l + 1 < m) res++, mr = e[i].r;
    }
    cout << res << endl;
    
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    
    int T = 1;
    cin >> T;
    while (T--) solve();
    
    return 0;
}