HDU1556Color the ball【标号法||树状数组】

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 using namespace std;
 5 
 6 const int maxn = 100005;
 7 int num[maxn];
 8 
 9 int main() {
10     int n;
11     int a, b;
12     while(scanf("%d",&n) && n) {
13         memset(num, 0, sizeof(num));
14         for(int i = 1; i <= n; i++) {
15             scanf("%d %d",&a, &b);
16             num[a]++; num[b + 1]--;
17         }
18         int c = 0;
19         int sum = 0;
20         for(int i = 1; i <= n; i++) {
21             sum += num[i];
22             printf(c++?" %d" : "%d", sum);
23         }
24         puts("");
25     }
26     return 0;
27 }

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 using namespace std;
 5 
 6 const int maxn = 100005;
 7 
 8 int c[maxn];
 9 
10 int lowbit(int x) {
11     return x & ( - x );
12 }
13 
14 int n;
15 void Add(int i, int num) {
16     while(i <= n) {
17         c[i] += num;
18         i += lowbit(i);
19     }
20 }
21 
22 int Sum(int i) {
23     int sum = 0;
24     while(i > 0) {
25         sum += c[i];
26         i -= lowbit(i);
27     }
28     return sum;
29 }
30 
31 int main() {
32     int a, b;
33     while(scanf("%d",&n) && n) {
34         memset(c, 0, sizeof(c));
35         for(int i = 1; i <= n; i++) {
36             scanf("%d %d",&a, &b);
37             Add(a, 1);
38             Add(b + 1, -1);
39         }
40         for(int i = 1; i <= n; i++) {
41             printf(i == 1 ? "%d" : " %d", Sum(i));
42         }
43         puts("");
44     }
45     return 0;
46 }