【ZOJ】3279 Ants

 1 #include<cstdio>

 2 #define MAXN 100010

 3 int tree[MAXN<<2];

 4 inline void PushUp(int rt)

 5 {

 6     tree[rt]=tree[rt<<1]+tree[rt<<1|1];

 7 }

 8 void Build(int L,int R,int rt)

 9 {

10     if(L==R)

11         scanf("%d",&tree[rt]);

12     else

13     {

14         int mid=(L+R)>>1;

15         Build(L,mid,rt<<1);

16         Build(mid+1,R,rt<<1|1);

17         PushUp(rt);

18     }

19 }

20 void Update(int x,int val,int L,int R,int rt)

21 {

22     if(L==R)

23         tree[rt]=val;

24     else

25     {

26         int mid=(L+R)>>1;

27         if(mid>=x)

28             Update(x,val,L,mid,rt<<1);

29         else

30             Update(x,val,mid+1,R,rt<<1|1);

31         PushUp(rt);

32     }

33 }

34 int Query(int x,int L,int R,int rt)

35 {

36     if(L==R)

37         return L;

38     int mid=(L+R)>>1;

39     if(x<=tree[rt<<1])

40         return Query(x,L,mid,rt<<1);

41     else

42     {

43         x-=tree[rt<<1];

44         return Query(x,mid+1,R,rt<<1|1);

45     }

46 }

47 int main()

48 {

49     int n,q,x,y;

50     char ch;

51     while(~scanf("%d",&n))

52     {

53         Build(1,n,1);

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

55         while(q--)

56         {

57             scanf(" %c%d",&ch,&x);

58             if(ch=='p')

59             {

60                 scanf("%d",&y);

61                 Update(x,y,1,n,1);

62             }

63             else

64                 printf("%d\n",Query(x,1,n,1));

65         }

66     }

67     return 0;

68 }