思路：

有點類似於區間修改點查詢的樹狀數組。

實現：

 1 #include <iostream>
 2 #include <cstdio>
 3 using namespace std;
 4 
 5 const int MAXN = 200005;
 6 int a[MAXN], n, k, q;
 7 
 8 int main()
 9 {
10         cin >> n >> k >> q;
11         for (int i = 0; i < n; i++)
12         {
13                 int
 
 l, r;
14                 scanf("%d %d", &l, &r);
15                 a[l]++; a[r + 1]--;
16         }
17         for (int i = 1; i < MAXN; i++) a[i] += a[i - 1];
18         for (int i = 1; i < MAXN; i++)
19                 if (a[i] >= k) a[i] = 1;
20                 else a[i] = 0;
21         for
 
 (int i = 1; i < MAXN; i++) a[i] += a[i - 1];
22         for (int i = 0; i < q; i++)
23         {
24                 int l, r;
25                 scanf("%d %d", &l, &r);
26                 printf("%d\n", a[r] - a[l - 1]);
27         }
28         return 0;
29 }

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