poj 3225 Help with Intervals

模版题，线段树区间赋值，反转，看别人代码敲的；

  1 #include<stdio.h>

  2 #include<string.h>

  3 #define MAXD 132000

  4 #define N 131070

  5 int tree[4 * MAXD], rev[4 * MAXD], to[4 * MAXD], a[MAXD];

  6 void build(int cur, int x, int y)

  7 {

  8     int mid = (x + y) >> 1, ls = cur << 1, rs = (cur << 1) | 1;

  9     tree[cur] = rev[cur] = 0;

 10     to[cur] = -1;

 11     if(x == y)

 12         return ;

 13     build(ls, x, mid);

 14     build(rs, mid + 1, y);

 15 }

 16 void pushdown(int cur)

 17 {

 18     int ls = cur << 1, rs = (cur << 1) | 1;

 19     if(to[cur] != -1)

 20     {

 21         to[ls] = to[rs] = to[cur];

 22         rev[ls] = rev[rs] = 0;

 23         tree[ls] = tree[rs] = to[cur];

 24         to[cur] = -1;

 25     }

 26     if(rev[cur])

 27     {

 28         rev[ls] = (rev[ls] + 1) & 1, rev[rs] = (rev[rs] + 1) & 1;

 29         tree[ls] ^= 1, tree[rs] ^= 1;

 30         rev[cur] = 0;

 31     }

 32 }

 33 void color(int cur, int x, int y, int s, int t, int c)

 34 {

 35     int mid = (x + y) >> 1, ls = cur << 1, rs = (cur << 1) | 1;

 36     if(x >= s && y <= t)

 37     {

 38         tree[cur] = to[cur] = c;

 39         rev[cur] = 0;

 40         return ;

 41     }

 42     pushdown(cur);

 43     if(mid >= s)

 44         color(ls, x, mid, s, t, c);

 45     if(mid + 1 <= t)

 46         color(rs, mid + 1, y, s, t, c);

 47 }

 48 void Reverse(int cur, int x, int y, int s, int t)

 49 {

 50     int mid = (x + y) >> 1, ls = cur << 1, rs = (cur << 1) | 1;

 51     if(x >= s && y <= t)

 52     {

 53         tree[cur] ^= 1;

 54         rev[cur] = (rev[cur] + 1) & 1;

 55         return ;

 56     }

 57     pushdown(cur);

 58     if(mid >= s)

 59         Reverse(ls, x, mid, s, t);

 60     if(mid + 1 <= t)

 61         Reverse(rs, mid + 1, y, s, t);

 62 }

 63 void dfs(int cur, int x, int y)

 64 {

 65     int mid = (x + y) >> 1, ls = cur << 1, rs = (cur << 1) | 1;

 66     if(x == y)

 67     {

 68         a[x] = tree[cur];

 69         return ;

 70     }

 71     pushdown(cur);

 72     dfs(ls, x, mid);

 73     dfs(rs, mid + 1, y);

 74 }

 75 void printresult()

 76 {

 77     int i, x, y, flag = 0;

 78     dfs(1, 0, N);

 79     for(i = 0; i <= N; i ++)

 80     {

 81         if(a[i])

 82         {

 83             if(flag)

 84                 printf(" ");

 85             else

 86                 flag = 1;

 87             if(i & 1)

 88                 printf("(%d,", i >> 1);

 89             else

 90                 printf("[%d,", i >> 1);

 91             for(; a[i + 1]; i ++);

 92             if(i & 1)

 93                 printf("%d)", (i + 1) >> 1);

 94             else

 95                 printf("%d]", i >> 1);

 96         }

 97     }

 98     if(flag == 0)

 99         printf("empty set\n");

100     printf("\n");

101 }

102 void solve()

103 {

104     int x, y;

105     char op[5], b[20];

106     while(scanf("%s%s", op, b) == 2)

107     {

108         sscanf(b + 1, "%d,%d", &x, &y);

109         if(b[0] == '(')

110             x = (x << 1) | 1;

111         else

112             x <<= 1;

113         if(b[strlen(b) - 1] == ')')

114             y = (y << 1) - 1;

115         else

116             y <<= 1;

117         if(op[0] == 'U')

118             color(1, 0, N, x, y, 1);

119         else if(op[0] == 'D')

120             color(1, 0, N, x, y, 0);

121         else if(op[0] == 'S')

122             Reverse(1, 0, N, x, y);

123         else if(op[0] == 'C')

124         {

125             if(x > 0)

126                 color(1, 0, N, 0, x - 1, 0);

127             if(y < N)

128                 color(1, 0, N, y + 1, N, 0);

129             Reverse(1, 0, N, x, y);

130         }

131         else

132         {

133             if(x > 0)

134                 color(1, 0, N, 0, x - 1, 0);

135             if(y < N)

136                 color(1, 0, N, y + 1, N, 0);

137         }

138     }

139     printresult();

140 }

141 int main()

142 {

143     build(1, 0, N);

144     solve();

145     return 0;

146 }