Hdu1166_敌兵布阵——线段树or树状数组

树状数组，插点问段

 1 #include<algorithm>

 2 #include<cstdio>

 3 #include<cstring>

 4 using namespace std;

 5 const int MAXN=50000+5;

 6 int c[MAXN];

 7 int lowbit(int x)

 8 {

 9     return x&(-x);

10 }

11 int sum(int x)

12 {

13     int temp=0;

14     while(x>0){

15         temp+=c[x];

16         x-=lowbit(x);

17     }

18     return temp;

19 }

20 void update(int x,int num,int n)

21 {

22     while(x<=n){

23         c[x]+=num;

24         x+=lowbit(x);

25     }

26 }

27 int main()

28 {

29     int test;

30     scanf("%d",&test);

31     for(int cas=1;cas<=test;cas++){

32         printf("Case %d:\n",cas);

33         int n;

34         scanf("%d",&n);

35         memset(c,0,sizeof(c));

36         int a;

37         for(int i=1;i<=n;i++){

38             scanf("%d",&a);

39             update(i,a,n);

40         }

41         char s[10];

42         int u,v;

43         loop:scanf("%s",&s);

44         if(s[0]=='A'){

45             scanf("%d%d",&u,&v);

46             update(u,v,n);

47             goto loop;

48         }

49         else if(s[0]=='S'){

50             scanf("%d%d",&u,&v);

51             update(u,-v,n);

52             goto loop;

53         }

54         else if(s[0]=='Q'){

55             scanf("%d%d",&u,&v);

56             printf("%d\n",sum(v)-sum(u-1));

57             goto loop;

58         }

59         else

60             continue;

61     }

62     return 0;

63 }

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线段树，单点修改

 1 #include<cstdio>

 2 #define lson l,m,rt<<1

 3 #define rson m+1,r,rt<<1|1

 4 const int maxn=50010;

 5 int sum[maxn<<2];

 6 void pushup(int rt)

 7 {

 8     sum[rt]=sum[rt<<1]+sum[rt<<1|1];

 9 }

10 void build(int l,int r,int rt)

11 {

12     if(l==r){

13         scanf("%d",&sum[rt]);

14         return ;

15     }

16     int m=(l+r)>>1;

17     build(lson);

18     build(rson);

19     pushup(rt);

20 }

21 void update(int p,int add,int l,int r,int rt)

22 {

23     if(l==r){

24         sum[rt]+=add;

25         return ;

26     }

27     int m=(l+r)>>1;

28     if(p<=m)

29         update(p,add,lson);

30     else

31         update(p,add,rson);

32     pushup(rt);

33 }

34 int query(int L,int R,int l,int r,int rt)

35 {

36     if(L<=l&&R>=r)

37         return sum[rt];

38     int m=(l+r)>>1;

39     int ret=0;

40     if(L<=m)

41         ret+=query(L,R,lson);

42     if(R>m)

43         ret+=query(L,R,rson);

44     return ret;

45 }

46 int main()

47 {

48     int test;

49     scanf("%d",&test);

50     for(int cas=1;cas<=test;cas++){

51         printf("Case %d:\n",cas);

52         int n;

53         scanf("%d",&n);

54         build(1,n,1);

55         char s[10];

56         int i,j;

57         while(scanf("%s",&s)){

58             if(s[0]=='A'){

59                 scanf("%d%d",&i,&j);

60                 update(i,j,1,n,1);

61             }

62             else if(s[0]=='S'){

63                 scanf("%d%d",&i,&j);

64                 update(i,-j,1,n,1);

65             }

66             else if(s[0]=='Q'){

67                 scanf("%d%d",&i,&j);

68                 printf("%d\n",query(i,j,1,n,1));

69             }

70             else if(s[0]=='E')

71                 break;

72         }

73     }

74     return 0;

75 }

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