【HDOJ】2795 Billboard

线段树。注意h范围（小于等于n）。

 1 #include <stdio.h>

 2 #include <string.h>

 3

 4 #define MAXN 200005

 5 #define lson l, mid, rt<<1

 6 #define rson mid+1, r, rt<<1|1

 7 #define mymax(x, y) (x>y) ? x:y

 8

 9 int nums[MAXN<<2];

10 int h, w;

11

12 void PushUP(int rt) {

13     nums[rt] = mymax(nums[rt<<1], nums[rt<<1|1]);

14 }

15

16 void build(int l, int r, int rt) {

17     int mid;

18     nums[rt] = w;

19

20     if (l == r)

21         return ;

22

23     mid = (l+r)>>1;

24     build(lson);

25     build(rson);

26 }

27

28 int query(int wi, int l, int r, int rt) {

29     int mid, ret;

30

31     if (l == r) {

32         nums[rt] -= wi;

33         return l;

34     }

35     mid = (l+r)>>1;

36

37     if (nums[rt<<1] >= wi)

38         ret = query(wi, lson);

39     else

40         ret = query(wi, rson);

41

42     PushUP(rt);

43     return ret;

44 }

45

46 int main() {

47     int n, wi;

48

49     while (scanf("%d%d%d", &h, &w, &n) != EOF) {

50         if (h > n)

51             h = n;      // h < n

52         build(1, h, 1);

53         while (n--) {

54             scanf("%d", &wi);

55             if (nums[1] < wi)

56                 printf("-1\n");

57             else

58                 printf("%d\n", query(wi, 1, h, 1));

59         }

60     }

61

62     return 0;

63 }

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