POJ 2777 Count Color(线段树 区间更新)

题目链接

根据区间更新的模版改改。线段树真的很不熟悉，交了很多次。

 1 #include <stdio.h>

 2 #include <string.h>

 3 #include <iostream>

 4 using namespace std;

 5 #define N 100001

 6 #define LL __int64

 7 int p[4*N],lz[4*N];

 8 void pushup(int rt)

 9 {

10     p[rt] = p[rt<<1]|p[rt<<1|1];

11 }

12 void pushdown(int rt)

13 {

14     if(lz[rt])

15     {

16         lz[rt<<1] = lz[rt];

17         lz[rt<<1|1] = lz[rt];

18         p[rt<<1] = lz[rt];

19         p[rt<<1|1] = lz[rt];

20         lz[rt] = 0;

21     }

22 }

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

24 {

25     int m;

26     lz[rt] = 0;

27     if(l == r)

28     {

29         p[rt] = 1;

30         return ;

31     }

32     m = (l+r)>>1;

33     build(l,m,rt<<1);

34     build(m+1,r,rt<<1|1);

35     pushup(rt);

36 }

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

38 {

39     int m,ans;

40     ans = 0;

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

42     {

43         return p[rt];

44     }

45     pushdown(rt);

46     m = (l+r)>>1;

47     if(L <= m)

48     ans |= query(L,R,l,m,rt<<1);

49     if(R > m)

50     ans |= query(L,R,m+1,r,rt<<1|1);

51     return ans;

52 

53 }

54 void update(int L,int R,int l,int r,int rt,int sc)

55 {

56     int m;

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

58     {

59         lz[rt] = sc;

60         p[rt] = sc;

61         return ;

62     }

63     pushdown(rt);

64     m = (l+r)>>1;

65     if(L <= m) update(L,R,l,m,rt<<1,sc);

66     if(R > m) update(L,R,m+1,r,rt<<1|1,sc);

67     pushup(rt);

68 }

69 int main()

70 {

71     int n,m,k,i,a,b,c,ans,t,j;

72     char ch[11];

73     while(scanf("%d%d%d",&n,&m,&k)!=EOF)

74     {

75         build(1,n,1);

76         for(i = 1;i <= k;i ++)

77         {

78             scanf("%s",ch);

79             if(ch[0] == 'C')

80             {

81                 scanf("%d%d%d",&a,&b,&c);

82                 if(a > b) swap(a,b);

83                 update(a,b,1,n,1,1<<(c-1));

84             }

85             else

86             {

87                 scanf("%d%d",&a,&b);

88                 if(a > b) swap(a,b);

89                 ans = query(a,b,1,n,1);

90                 t = 0;

91                 for(j = 0;j < m;j ++)

92                 if(ans&(1<<j))

93                 t ++;

94                 printf("%d\n",t);

95             }

96         }

97     }

98     return 0;

99 }