hdu1556 Color the ball

Posted 2020-10-24 王宜鸣

思路：

线段树区间更新模板。

实现：

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 const int N = 100005;
 4 int tree[N * 4], lazy[N * 4], a[N];
 5 int n;
 6 
 7 void build()
 8 {
 9     memset(tree, 0, sizeof tree);
10     memset(lazy, 0, sizeof lazy);
11 }
12 
13 void pushdown(int num)
14 {
15     if (!lazy[num]) return;
16     tree[num * 2] += lazy[num];
17     tree[num * 2 + 1] += lazy[num];
18     lazy[num * 2] += lazy[num];
19     lazy[num * 2 + 1] += lazy[num];
20     lazy[num] = 0;
21 }
22 
23 void update(int num, int l, int r, int x, int y, int dx)
24 {
25     if (x <= l && y >= r) { tree[num] += dx; lazy[num] += dx; return; }
26     pushdown(num);
27     int m = l + r >> 1;
28     if (x <= m) update(num * 2, l, m, x, y, dx);
29     if (y >= m + 1) update(num * 2 + 1, m + 1, r, x, y, dx);
30     tree[num] = tree[num * 2] + tree[num * 2 + 1];
31 }
32 
33 int query(int num, int l, int r, int x, int y)
34 {
35     if (x <= l && y >= r) return tree[num];
36     pushdown(num);
37     int m = l + r >> 1, ans = 0;
38     if (x <= m) ans += query(num * 2, l, m, x, y);
39     if (y >= m + 1) ans += query(num * 2 + 1, m + 1, r, x, y);
40     return ans;
41 }
42 
43 int main()
44 {
45     ios::sync_with_stdio(false);
46     while (cin >> n, n)
47     {
48         build();
49         int a, b;
50         for (int i = 0; i < n; i++) { cin >> a >> b; update(1, 1, n, a, b, 1); }
51         for (int i = 1; i <= n; i++) cout << query(1, 1, n, i, i) << " ";
52         cout << endl;
53     }
54     return 0;
55 }